Biology HSC Notes by syllabus points · Examining frequency data: ... Content Descriptor: Investigate the use of technologies to determine inheritance patterns in a ... Trends and

BIOLOGY HSC NOTES BY

SYLLABUS POINTS 2019 HSC Syllabus

Mitch Millett [email protected]

Summary Detailed notes on the 2019 Biology Syllabus by dot points. Designed for educational purposes.

Use relevant hyperlinks to navigate to the desired descriptor in the syllabus. Data provided

may be incorrect or out of date

Version 1.F

Mitch Millett Return

1

Module 5: Heredity ................................................................................................................................. 8

Inquiry Question 1: How does reproduction ensure the continuity of a species? ............................... 8

Content Descriptor: Explain the mechanisms of reproduction that ensure the continuity of a

species, by analysing sexual and asexual methods of reproduction in a variety of organisms,

including but not limited to: ............................................................................................................ 8

Animals: advantages of external and internal fertilisation (5.1.1) ............................................. 8

Plants: asexual and sexual reproduction (5.1.2) ........................................................................ 8

Fungi: budding, spores (5.1.3) .................................................................................................. 12

Bacteria: Binary fission (5.1.4) ................................................................................................. 12

Protists: Binary fission, budding (5.1.5) ................................................................................... 13

Content Descriptor: Analyse the features of fertilisation, implantation and hormonal control of

pregnancy and birth in mammals: (5.1.6) ..................................................................................... 13

Content Descriptor: Evaluate the impact of scientific knowledge on the manipulation of plant and

animal reproduction in agriculture: (5.1.7) ................................................................................... 17

Inquiry Question Review: How does reproduction ensure the continuity of a species? (5.1.8) ... 18

Inquiry Question 2: How important is it for genetic material to be replicated exactly? ................... 19

Content Descriptor: Model the processes involved in cell replication, including, but not limited

to: .................................................................................................................................................. 19

Mitosis and Meiosis: (5.2.1) ..................................................................................................... 19

DNA replication using the Watson and Crick DNA model, including nucleotide composition,

pairing and bonding: (5.2.2) ..................................................................................................... 20

Assess the effect of cell replication processes on the continuity of species: (5.2.3) ................. 21

Inquiry Question Review: How does reproduction ensure the continuity of a species? (5.2.4) ... 22

Inquiry Question 3: Why is polypeptide synthesis important? ......................................................... 22

Content Descriptor: Construct appropriate representations to model and compare the forms in

which DNA exists in prokaryotes and eukaryotes: (5.3.1) ........................................................... 22

Content Descriptor: Model the process of polypeptide synthesis including: ................................ 22

Transcription and translation: (5.3.2) ...................................................................................... 22

Assessing the importance of mRNA and tRNA in transcription and translation: (5.3.3).......... 23

Analysing the function and importance of polypeptide synthesis: (5.3.4) ................................ 23

Assessing how genes and environment affect phenotypic expression: (5.3.5) .......................... 24

Content descriptor: Investigate the structure and function of proteins in living things: (5.3.6).... 24

Inquiry Question Review: Why is polypeptide synthesis important? (5.3.7) ............................... 25

Inquiry Question 4: How can the genetic similarities and differences within and between species be

compared? ......................................................................................................................................... 25

Content Descriptor: Conduct practical investigation to predict the variation in the genotype of

offspring by modelling meiosis, including the crossing over of homologous chromosomes,

fertilisation and mutations: (5.4.1) ................................................................................................ 25

Content Descriptor: Model the formation of new combination of genotypes produced during

meiosis, including but not limited to: ............................................................................................ 26


2

Interpreting examples of autosomal, sex-linkage, co-dominance, incomplete dominance and

multiple alleles: (5.4.2) ............................................................................................................. 26

Constructing and interpreting information and data from pedigrees and Punnett squares:

(5.4.3) ........................................................................................................................................ 28

Content Descriptor: Collect, record and present data to represent frequencies of some

characteristics in order to identify trends, patterns, relationships and limitation in data, for

example: ........................................................................................................................................ 29

Examining frequency data: (5.4.4) ........................................................................................... 29

Analysing single nucleotide polymorphism (SNP): (5.4.5) ....................................................... 29

Inquiry Question Review: How can the genetic similarities and differences within and between

species be compared? (5.4.6) ........................................................................................................ 30

Inquiry Question 5: Can population genetic patterns be predicted with any accuracy? ................... 30

Content Descriptor: Investigate the use of technologies to determine inheritance patterns in a

population using, for example: ...................................................................................................... 30

DNA sequencing and profiling: (5.5.1) ..................................................................................... 30

Content Descriptor: Investigate the use of data analysis from a large-scale collaborative project

to identify trends, patters and relationships, for example: ............................................................ 31

The use of population genetics data in conservation management: (5.5.2) .............................. 31

Population genetics studies used to determine the inheritance of a disease or disorder: (5.5.3)

.................................................................................................................................................. 31

Population genetics relating to human evolution: (5.5.4) ........................................................ 31

Inquiry Question Review: How can the genetic similarities and differences within and between

species be compared? (5.5.5) ........................................................................................................ 31

Module 6: Genetic Change ................................................................................................................... 33

Inquiry Question 1: How does mutation introduce new alleles into a population? .......................... 33

Content Descriptor: Explain how a range of mutagens operate, including but not limited to: ..... 33

Electromagnetic radiation sources (6.1.1)................................................................................ 33

Chemicals (6.1.2) ...................................................................................................................... 33

Naturally occurring mutagens (6.1.3) ....................................................................................... 33

Content Descriptor: Compare the causes, processes and effects of different types of mutation,

including but not limited to: .......................................................................................................... 33

Point mutation (6.1.4) ............................................................................................................... 33

Chromosomal mutation (6.1.5) ................................................................................................. 34

Content Descriptor: Distinguish between somatic mutations and germ-line mutations and their

effect on an organism: (6.1.6) ....................................................................................................... 35

Content Descriptor: Assess the significance of ‘coding’ and ‘non-coding’ DNA segments in the

process of mutation: (6.1.7) .......................................................................................................... 35

Content Descriptor: Investigate the causes of genetic variation relation to the processes of

fertilisation, meiosis and mutation: (6.1.8) ................................................................................... 36

Content Descriptor: Evaluate the effect of mutation, gene flow and genetic drift on the gene pool

of populations: (6.1.9) ................................................................................................................... 36


3

Inquiry Question Review: How does mutation introduce new alleles into a population? (6.1.10)

...................................................................................................................................................... 37

Inquiry Question 2: How do genetic techniques affect Earth’s biodiversity? ................................... 37

Content Descriptor: Investigate the uses and applications of biotechnology (past, present and

future), including: ......................................................................................................................... 37

Analysing the social implications and ethical uses of biotechnology, including plant and

animal examples (6.2.1) ............................................................................................................ 37

Researching future directions of the use of biotechnology: (6.2.2) .......................................... 38

Evaluating the potential benefits for society of research using genetic technologies: (6.2.3) .. 39

Evaluating the changes to Earth’s biodiversity due to genetic techniques: (6.2.4) .................. 39

Inquiry Question Review: How does mutation introduce new alleles into a population? (6.2.5) . 40

Inquiry Question 3: Does artificial manipulation of DNA have the potential to change populations

forever? ............................................................................................................................................. 40

Content Descriptor: Investigate the uses and advantages of current genetic technologies that

induce genetic change: (6.3.1) ...................................................................................................... 40

Content Descriptor: Compare the processes and outcomes of reproductive technologies,


Artificial insemination: (6.3.2) .................................................................................................. 40

Artificial pollination: (6.3.3) ..................................................................................................... 40

Content Descriptor: Investigate and assess the effectiveness of cloning, including but not limited

to: .................................................................................................................................................. 41

Whole organism cloning: (6.3.4) .............................................................................................. 41

Gene cloning: (6.3.5) ................................................................................................................ 41

Content Descriptor: Describe techniques and applications used in recombinant DNA technology,

for example: .................................................................................................................................. 42

The development of transgenic organisms in agricultural and medical applications: (6.3.6) . 42

Content Descriptor: Evaluate the benefits of using genetic technologies in agricultural, medical

and industrial applications: (6.3.7) ................................................................................................ 42

Content Descriptor: Evaluate the effect on biodiversity of using biotechnology in agriculture:

(6.3.8) ............................................................................................................................................ 42

Content Descriptor: Interpret a range of secondary sources to assess the influence of social,

economic and cultural contexts on a range of biotechnologies: (6.3.9) ........................................ 43

Inquiry Question Review: Does artificial manipulation of DNA have the potential to change

populations forever? (6.3.10) ........................................................................................................ 43

Module 7: Infectious Disease ................................................................................................................ 44

Inquiry Question 1: How are diseases transmitted? .......................................................................... 44

Content Descriptor: Describe a variety of infectious diseases caused by pathogens, including

microorganisms and macroorganisms and non-cellular pathogens, and collect primary and

secondary sourced data and information relating to disease transmission, including: .................. 44

Classifying different pathogens that cause disease in plants and animals (7.1.1) .................... 44

Investigating the transmission of a disease during an epidemic: (7.1.2) .................................. 44


4

Design and conduct a practical investigation relation to the microbial testing of water or food

samples: (7.1.3) ......................................................................................................................... 44

Investigate modes of transmission of infectious diseases, including direct contact, indirect

contact and vector transmission: (7.1.4) .................................................................................. 45

Content Descriptor: Investigate the work of Robert Koch and Louis Pasteur, to explain the causes

and transmission of infectious disease, including: ........................................................................ 45

Koch’s postulates: (7.1.5) ......................................................................................................... 45

Pasteur’s experiments on microbial contamination (7.1.6) ...................................................... 46

Content Descriptor: Assess the causes and effects of diseases on agricultural production,


Plant diseases: (7.1.7) ............................................................................................................... 47

Animal diseases: (7.1.8) ............................................................................................................ 47

Content Descriptor: Compare the adaptations of different pathogens that facilitate entry into and

transmission between hosts: (7.1.9) .............................................................................................. 48

Inquiry Question Review: How are diseases transmitted? (7.1.10) .............................................. 49

Inquiry Question 2: How does a plant or animal respond to infection? ............................................ 49

Content Descriptor: Investigate the response of a named Australian plant to a named pathogen

through practical and/or secondary-sourced investigation, for example: ..................................... 49

Fungal pathogens: (7.2.1) ......................................................................................................... 49

Viral pathogens: (7.2.2) ............................................................................................................ 49

Content Descriptor: Analyse responses to the presence of pathogens by assessing the physical

and chemical changes that occur in the host animal’s cells and tissues: (7.2.3) ........................... 50

Inquiry Question Review: How does a plant or animal respond to infection? (7.2.4) .................. 50

Inquiry Question 3: How does the human immune system respond to exposure to a pathogen? ..... 50

Content Descriptor: Investigate and model the innate and adaptive immune systems in the human

body: (7.3.1) .................................................................................................................................. 50

Content Descriptor: Explain how the immune system responds after primary exposure to a

pathogen, including innate and acquired immunity: (7.3.2) ......................................................... 52

Inquiry Question Review: How does the human immune system respond to exposure to a

pathogen? (7.3.3) .......................................................................................................................... 54

Inquiry Question 4: How can the spread of infectious disease be controlled? ................................. 54

Content Descriptor: Investigate and analyse the wide range of interrelated factors involved in

limiting local, regional and global spread of a named infectious disease: (7.4.1) ........................ 54

Content Descriptor: Investigate procedures that can be employed to prevent the spread of

disease, including but not limited to: ............................................................................................ 55

Hygiene practices: (7.4.2) ......................................................................................................... 55

Quarantine: (7.4.3) ................................................................................................................... 55

Vaccination, including active and passive immunity: (7.4.4) ................................................... 55

Public health campaigns: (7.4.5) .............................................................................................. 56

Use of Pesticides: (7.4.6) .......................................................................................................... 56


5

Genetic engineering: (7.4.7) ..................................................................................................... 56

Content Descriptor: Investigate and assess the effectiveness of pharmaceuticals as treatment

strategies for the control of infectious disease for example: ......................................................... 56

Antivirals: (7.4.8) ...................................................................................................................... 56

Antibiotics: (7.4.9) .................................................................................................................... 56

Content Descriptor: Investigate and evaluate environmental management and quarantine methods

used to control an epidemic or pandemic: (7.4.10) ....................................................................... 57

Content Descriptor: Interpret data relating to the incidence and prevalence of infectious disease

in populations, for example: .......................................................................................................... 57

Mobility of individuals and the portion that are immune or immunised: (7.4.11) .................... 57

Malaria or Dengue Fever in South East Asia: (7.4.12) ............................................................ 59

Content Descriptor: Evaluate historical, culturally diverse and current strategies to predict and

control the spread of disease: (7.4.13) .......................................................................................... 59

Content Descriptor: Investigate the contemporary applications of Aboriginal protocols in the

development of particular medicines and biological materials in Australia and how recognition

and protection of Indigenous cultural and intellectual property is important, for example: ......... 60

Bush medicine: (7.4.14) ............................................................................................................ 60

Smoke bush in Western Australia: (7.4.15) ............................................................................... 60

Inquiry Question Review: How can the spread of infectious disease be controlled? (7.4.16) ...... 61

Module 8: Non-infectious Disease and Disorders ................................................................................ 62

Inquiry Question 1: How is an organism’s internal environment maintained in response to a

changing external environment? ....................................................................................................... 62

Content Descriptor: Construct and interpret negative feedback loops to show homeostasis by

using a range of sources, including but not limited to: ................................................................. 62

Temperature: (8.1.1) ................................................................................................................. 62

Glucose: (8.1.2) ........................................................................................................................ 63

Content Descriptor: Investigate the various mechanisms used by organisms to maintain their

internal environment within tolerance limits, including: .............................................................. 63

Trends and patterns in behavioural, structural and physiological adaptations in endotherms

that assist in maintaining homeostasis: (8.1.3) ......................................................................... 63

Internal coordination systems that allow homeostasis to be maintained, including hormones

and neural pathways: (8.1.4) .................................................................................................... 64

Mechanisms in plants that allow water balance to be maintained: (8.1.5) .............................. 65

Inquiry Question Review: How is an organism’s internal environment maintained in response to

a changing external environment? (8.1.6) ..................................................................................... 66

Inquiry Question 2: Do non-infectious diseases cause more deaths than infectious disease? .......... 66

Content Descriptor: Investigate the causes and effects of non-infectious diseases in humans,


Genetic diseases: (8.2.1) ........................................................................................................... 66

Diseases caused by environmental exposure: (8.2.2) ............................................................... 66

Nutritional diseases: (8.2.3)...................................................................................................... 67


6

Cancer: (8.2.4) .......................................................................................................................... 67

Content Descriptor: Collect and represent data to show the incidence, prevalence and mortality

rates of non-infectious diseases for example: ............................................................................... 67


Diseases caused by environmental exposure: (8.2.6) ............................................................... 68

Inquiry Question Review: Do non-infectious diseases cause more deaths than infectious? (8.1.7)

...................................................................................................................................................... 69

Inquiry Question 3: Why are epidemiological studies used? ............................................................ 70

Content Descriptor: Analyse patterns of non-infectious diseases in populations, including their

incidence and prevalence, including not limited to: ...................................................................... 70


Disease caused by environmental exposure: (8.3.2) ................................................................. 71

Content Descriptor: Investigate the treatment/management, and possible future directions for

further research, of a non-infectious disease using an example from one of the non-infectious

disease categories listed above: (8.3.3) ......................................................................................... 71

Content Descriptor: Evaluate the method used in an example of an epidemiological study: (8.3.4)

...................................................................................................................................................... 72

Content Descriptor: Evaluate, using examples, the benefits of engaging in an epidemiological

study: (8.3.5) ................................................................................................................................. 72

Inquiry Question Review: Why are epidemiological studies used? (8.3.6) .................................. 73

Inquiry Question 4: How can non-infectious disease be prevented? ................................................ 73

Content Descriptor: Use secondary sources to evaluate the effectiveness of current disease-

prevention methods and develop strategies for the prevention of a non-infectious disease,


Educational programs and campaigns: (8.4.1) ........................................................................ 73

Genetic engineering: (8.4.2) ..................................................................................................... 73

Inquiry Question Review: How can non-infectious disease be prevented? (8.4.3) ...................... 73

Inquiry Question 5: How can technologies be used to assist people who experience disorders? ..... 74

Content Descriptor: Explain a range of causes of disorders by investigating the structures and

functions of the relevant organs, for example: .............................................................................. 74

Hearing loss: (8.5.1) ................................................................................................................. 74

Visual disorders: (8.5.2) ........................................................................................................... 75

Loss of kidney function: (8.5.3) ................................................................................................. 76

Content Descriptor: Investigate technologies that are used to assist with the effects of a disorder,


Hearing loss: cochlear implants, bone conduction implants, hearing aids: (8.5.4) ................. 76

Visual disorders: spectacles, laser surgery: (8.5.5) ................................................................. 77

Loss of kidney function: dialysis: (8.5.6) .................................................................................. 77

Content Descriptor: Evaluate the effectiveness of a technology that is used to manage and assist

with the effects of a disorder: (8.5.7) ............................................................................................ 77


7


8

Module 5: Heredity

Inquiry Question 1: How does reproduction ensure the continuity of a

species?

Content Descriptor: Explain the mechanisms of reproduction that ensure the continuity

of a species, by analysing sexual and asexual methods of reproduction in a variety of

organisms, including but not limited to:

Animals: advantages of external and internal fertilisation (5.1.1)

Internal and external

Aquatic environment Terrestrial environment

External

fertilisation • Usually highly successful, as

gametes do not dehydrate.

• Must produce high numbers due

to losses from predators and

environment

• Performed by fish, coral

• Not successful due to gamete’s

reliance upon a watery

environment, gametes will

desiccate

Internal fertilisation • Usually successful, causing

fewer gametes to be required

• Energy efficient

• May cause issues with need for

water to pass over gills

• Performed by some species of

sharks

• Used to overcome need for

water in fertilisation

• Direct transfer of gametes

avoids loss by dispersal and

dehydration

• Very high success rates, as the

internal environment protects

from disease

• Performed by mammals such as

humans

Plants: asexual and sexual reproduction (5.1.2)

Sexual and asexual

Type of

reproduction

Sexual reproduction Asexual reproduction

Number of parents Requires two parents Requires one parent

Genetic variation Provides genetic variation in

offspring:

• This makes it useful when

environmental conditions

change, as random traits

may be more suitable to the

environment.

Does not provide genetic variation in offspring:

• Does not allow offspring to become

more adapted to the environment

• However, this does allow beneficial

traits to be passed on directly to

offspring. This allows for rapid

reproduction in a known environment.

Uniting of gametes Requires the uniting of gametes Certain types of parthenogenic organisms do unite

gametes during asexual reproduction, but for the

most part, does not require uniting of gametes

Number of

offspring/energy

consumption

Produces relatively low number of

off-spring with significant energy

input

Produces a relatively high number of off-spring

with low energy input

Examples of

organism • Humans

• Angiosperms

• Plasmodium

• Bacteria

• Grasses

• Plasmodium

Asexual reproduction:


9

➢ Runners

A technique performed by grasses in which shoots of grass grow outwards away from the main plant.

Lobes on this runner grow into the ground. While these are connected to begin with, they can survive

as distinct organisms.

➢ Root tubers

Roots which become swollen with food can grow to become distinct organisms. This is used by plants

such as potatoes.

➢ Bulbs

Bulbs which asexually form off each other, such as those in onions.

➢ Budding


10

New plants develop as outgrowths from the parent plant. Used by plants such as the spider bush.

➢ Apomixis

Used by plants such as orange trees and dandelions. Embryos in the seed can be produced using the

sexual reproduction system of the parent plant. This means that the plant passes on its beneficial traits

to its offspring, while still obtaining the range of distribution gained by seed dispersion.

➢ Layering

Branches which are touching the ground may grow into roots and begin to produce a new tree.

➢ Totipotency

Method created by humans to produce a high yield of identical clones of a single plant. A hold punch

of cells is taken from a plant. These cells are grown in nutrient gel, then separated into individual cells

and grown through targeted hormones. Each individual cell can produce identical plants to the

original, allowing the cloning of plants that have traits beneficial to humans.

Sexual reproduction:

➢ Aquatic Plants

Aquatic non-vascular plants were some of the first multicellular organisms. Very similar to coral, they

have little need to protect their sperm, as they can rely on water to keep the gamete hydrated and

currents to move it to another plants reproductive system.

➢ Gymnosperms

Meaning “naked seed” the seed is not enclosed in an ovule. An example of this is pine cones.

➢ Angiosperms

Angiosperms are the only plants which have flowers, which are used to deliberately attract pollinators

to the flower, with some even producing nectar to entice pollinators. The male reproductive system of

these flowers is called the stamen and the pollen is released from the anthers. The female reproductive

system is called the carpel, pollen is received by the stigma. Once the pollen has landed on the stigma,

the sperm grows down into the egg, fertilising it. A second sperm nucleus fuses with this zygote

producing the endosperm, which nourishes the seed. Fleshy fruit then grows around seeds to protect

them and offer a dispersal mechanism.

Sometimes plants deliberately self-fertilise in order to reproduce, however some plants avoid this and

terminate the zygote. Note that this is not asexual as it still requires the uniting of gametes.

Note that angiosperms which contain both male and female systems are called perfect flowers.


11

Pollination:

➢ Insect pollinated

Bright colours, usually yellow, with a strong scent. May include a landing strip or specific sized cleft

for the entry of the insect. The pollen is usually sticky.

➢ Bird pollinated

Bright colours such as red but usually lacking a scent. Flowers and stems are usually larger and

stronger.

➢ Wind pollinated

Extremely light pollen placed upon extremities high in the air. Nor colours or scents required.


12

Seed dispersal:

➢ Animals

Animals ingesting seeds, which are then deposited in faeces as fertilizer. An example of this is

redcurrants. Seeds may also latch onto moving animals to travel large distances. Seeds which use

animals for dispersal are characterised by bright colours and easily accessible berries.

➢ Wind

Lightweight seeds are carried by the wind. An example of this is dandelions.

➢ Water

Hollow or lightweight structures float on water to travel an incredible distance. Examples include

coconuts and mangroves.

➢ Self

Seeds are dropped by the plant and deposited nearby. This is either done through gravity such as pine

cones, or some sort of propulsion such as touch-me-not or the exploding cucumber

Fungi: budding, spores (5.1.3)

Methods of fungi reproduction:

Asexual Sexual

Method without spores Fragmentation of filament

mass called mycelium which

each produces individuals.

May also undergo budding,

with the nucleus dividing

and a bulge forms on the

side of cell before detaching

as a new organism

None

Method with spores Asexual spore production

cloning of parent plant DNA

Plasmogamy is the uniting of

haploid spore cells to form a

diploid spore.

Bacteria: Binary fission (5.1.4)

Bacteria reproduction:


13

The genetic information for prokaryotes is found in the nucleoid region. Further DNA can be found in

plasmids, which provides additional capabilities such as antibiotic resistance. These traits can be

shared through conjugation. Bacteria reproduce via the process of binary fission, where one cell splits

in two, which occurs on the origin of replication of the bacterial chromosome. During fission, this

section replicates, moves to the other side of the cell. The cell then elongates and then splits.

Protists: Binary fission, budding (5.1.5)

Protist reproduction:

Due to the genetic diversity of protists as a term, there a variety of techniques employed to reproduce.

One asexual method is by binary fission, in which increase their size over a period of growth, before

the cell undergoes a nuclear division, splitting the cell in two. Alternatively, budding involves an

identical clone of the parent growing as an off-shoot before it detaches and becomes its own

organism. Some protists undergo a stage of meiosis, after which two haploid cells meet to form a

zygote which then grows to become multicellular.

Content Descriptor: Analyse the features of fertilisation, implantation and hormonal

control of pregnancy and birth in mammals: (5.1.6)

Gametogenesis:

The production of gametes can be considered the start of the reproductive cycle in mammals. Meiosis

results in haploid gametes that can each contain half the chromosomes of the parent.

Oogenesis:


14

Women are born with all of their primary oocytes. Meiosis begins with the development of the

primary oocytes in follicles, but halts before birth and only continues after puberty. Polar bodies are

created at each phase of telophase, with the last polar body only being created at fertilisation. Since no

knew eggs are created, there is a higher chance of infertility in women.

Spermatogenesis:

The production of sperm can occur late into elderly age, however it slows down with the reduction of

testosterone in the system. Occurs in the standard processes of spermatogenesis.

Fertilisation:

The fusion of haploid gametes to form a diploid zygote, a single celled egg. The embryo begins

dividing and travels down the nucleus, undergoing 5-6 miotic divisions. At this point, the egg must be

differentiated enough to implant into the uterine wall.


15

Hormones:


16

Human chorionic gonadotropin (hCG) is an embryonic hormone produced by the blastocyst during

implantation. hCG maintains the corpus luteum, which during the early months of pregnancy

produces progesterone. hCG is needed in high concentrations and as such is secreted in urine; some

early pregnancy tests detect hCG.

Progesterone:

➢ Increase of blood flow to the uterus

➢ Stimulates the lining of the womb and establishing the placenta

➢ Prevents the onset of labour.

➢ Begins to be produced by the placenta after 6-9 weeks

Oestrogen:

➢ Stimulates and regulated other hormones

➢ Promotes breast growth

➢ Development of the endometrium

FSH (follicle stimulating hormone):

➢ Secreted by anterior pituitary gland stimulating the maturation of follicles

LH (luteinizing hormone):

➢ Secreted by anterior pituitary gland stimulates ovulation and the development of the corpus

luteum.

Menstrual cycle activity:

1. Hypothalamus secretes GnRH (Gonadotropin-releasing hormone).

2. Pituitary secretes LH (luteinizing hormone) and FHS (follicle stimulating hormone).

3. Oestrogen is secreted.

4. Follicles mature and ovulation occurs.

5. Corpus luteum forms from mature follicle and secretes progesterone and oestrogen.

6. Pituitary releases inhibin to halt secretion of LH and FSH

Implantation:

Attachment and invasion of the uterus by the blastocyst. In humans this usually occurs 8-10 days after

ovulation. If implantation is not sufficiently proceeded, hormonal feedback may not occur leading to

the next pregnancy and the loss of the foetus.

Stages of labour:

➢ Dilation

Lasts for 2-20 hours and includes the time between the onset of labour and the full dilation of the

cervix. Amniotic sac may rupture during this time. Oxytocin stimulates contractions, associated with

the pain of labour.

➢ Expulsion

Rhythmic contractions push the baby to the end of the vagina. Delivery completes expulsion.

➢ Delivery of the placenta

Expulsion of the placenta

Non-copulative fertilisation in humans:


17

➢ Artificial insemination

An extremely cheap method provided there is easy access to sperm. Sperm is implanted into the

mother manually through the vagina using a syringe. AI in humans tends to have low success rates, or

similar to those of regular sex.

➢ Inter-uterine insemination

More invasive than artificial insemination but tends to have higher success rates as the sperm is

delivered through the cervix into the uterus. Generally, also more expensive than AI.

➢ In-vitro fertilisation (IVF)

An expensive method that can only be performed if the mother maintains healthy eggs. Usually

performed after exhaustion of other methods. Can also be useful if the mother is unable to carry the

child themselves; use of a surrogate.

Content Descriptor: Evaluate the impact of scientific knowledge on the manipulation of

plant and animal reproduction in agriculture: (5.1.7)

Selective Breeding:

Selective breeding and the subsequent domestication of animals has been a part of human culture for

roughly 11,000 years. While the mechanisms which enabled this selection of specific traits through

breeding programs was not specifically known, these methods were used to improve quality of food

and agriculture. One example of this was in the cultivation of bananas, which used to once have low

yields of fruit and large seeds. The impact of this selective breeding of plants can be seen in. These

methods have been epitomised with the widespread use of artificial insemination and artificial

pollination in agriculture.


18

Scientific knowledge and understanding of the natural processes of inheritance has both enabled and

encouraged these developments. Another example of selective breeding is the selection of dairy cows

which produce A2 protein in their milk, which was found to correlate with a higher yield of milk.

Thus, advanced in both detection mechanisms and close examination of genotypic relations enabled

the increase in efficiency of the dairy industry.

Inquiry Question Review: How does reproduction ensure the continuity of a species?

(5.1.8)

You should be able to:

➢ Describe the different types of reproduction

➢ Explain sexual reproduction in mammals with reference to gametogenesis and hormonal

control.

➢ Explain how scientific knowledge of the processes of reproduction have enabled their

artificial manipulation.

Sample Questions:

Discuss the relative success of external and internal fertilisation in relation to the colonisation of the

land:

The very first animals developed in the ocean, using external fertilisation as the watery environment

prevented the eggs from desiccating. However, water environments can easily disperse eggs and

sperm, leading to a lower chance of fertilisation. Furthermore, since there is only a small sac or fluid

around embryos, the survival rate is very low, with many being eaten by predators or dying from

disease. As animals moved onto land, they needed to protect the embryo from desiccation. This

resulted in the adaptation of internal fertilisation; the gametes uniting inside the mother. Since the

sperm is deposited and contained inside the mother, fertilisation rates are relatively high. In contrast to

external fertilisation, the mechanisms to protect the embryo during development (pouches, hard eggs

shells, internal development) protected the embryos from predators, disease and desiccation,

culminating in a far higher success rate.

Technology Method Impact on population

Artificial insemination

Semen is harvested from bulls. This semen

is injected using a syringe into vagina of a

female cow, timed with menstrual cycles to

ensure highest chance of success. Mates are

chosen to produce desirable offspring.

Produces offspring with

desirable characteristics such as

higher meat quantity. Tends to

reduce biodiversity which may

make population more

susceptible to disease. May also

increase bio-diversity through

uniting geographically separated

gametes.

Artificial pollination

Pollen from selected plants is collected on

the stamen of male flowers, while the

undesirable plants have their stamen

removed by trimming. This pollen is

delivered manually such as via paintbrush

to the stigma of female plants. Mating

plants are chosen to produce desirable

characteristics.

Produces offspring with

desirable characteristics such as

smaller seeds. May reduce

biodiversity, however plants can

easily incorporate foreign

aspects of genome into their

own. May also increase bio-

diversity through uniting

geographically separated

gametes.


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Analyse the possible ways in which a lemon tree can reproduce:

A lemon tree has a variety of mechanisms which it can use to reproduce. Firstly, it may reproduce

sexually, through encouraging bees as its pollinator to transfer pollen from one lemon tree to the

stigma on another tree. This causes genetic variation in the offspring which may be useful for new

adaptations, and also enables long range seed dispersal. In rare cases, lemon trees may self-pollinate.

While this maintains the advantages of seed dispersal, it does not achieve genetic variation. Similarly,

apomixis, an asexual reproduction method in which the seeds are clones of the parents, has the

advantage of seed dispersal but lacks genetic variation. Branches which touch the ground may also

reproduce sexually through layering, which can be beneficial if the tree has fallen over. Finally, of

significant value to humans is the totipotent reproduction, which can be used to directly clone

identical plants from a single graft.

Inquiry Question 2: How important is it for genetic material to be

replicated exactly?

Content Descriptor: Model the processes involved in cell replication, including, but not

limited to:

Mitosis and Meiosis: (5.2.1)

Mitosis:

Interphase – The normal function of the cell. In this phase, the single strand chromosomes divide into

double stranded chromosomes. Membrane begins to disintegrate.

Prophase – Chromosomes condense, becoming visible in their double stranded form.

Metaphase – Middle phase, double stranded chromosomes line up in the centre of the cell, attached to

miotic spindles.

Anaphase – Centromeres divide, pulling the chromatids apart into single strands.

Telophase – Two nuclei form.

Cytokinesis – Fluid (cytoplasm) divides.


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Meiosis:

Meiosis and mitosis:

DNA replication using the Watson and Crick DNA model, including nucleotide

composition, pairing and bonding: (5.2.2)

History of Watson and Crick:

In the 1940’s it was hypothesized that heredity was caused by and carried on proteins. This was

contradicted however by Watson and Crick in 1953 through some unethically liberated help from

Rosalind Franklin, who discovered that DNA formed a double helix structure, and the coding was

performed by 4 nitrogenous bases.


21

Stages of DNA replication:

1. Initiation – Helicase enzyme unwinds the double helix. Cell also creates a short sequence of

RNA primers

2. Elongation – Polymerase enzyme controls elongation, occurring in a 5’➔ 3’ direction adding

complementary nucleic bases.

3. Termination – Ligase enzyme snips off a section of telomere at the end of replication.

Assess the effect of cell replication processes on the continuity of species: (5.2.3)

Mitosis

Mitosis ensures the continuity of the species through allowing organism growth and repair. This

allows an organism to grow and survive to sexual maturity to continue the genes of the species. It is

important that this DNA is replicated exactly to ensure the daughter cells perform the same function

as the parent.

Meiosis

Ensures continuity through providing genetic variation for the resultant daughter cells. This genetic

variation provides the different combination of genetic information (alleles) upon which the

mechanism of natural selection acts. Thus, meiosis ensures that organisms are genetically varied,

ensuring that the species can adapt to changes in the environment.


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Inquiry Question Review: How does reproduction ensure the continuity of a species?

(5.2.4)


➢ Describe the Watson and Crick genetic model and DNA replication.

➢ Describe meiosis and mitosis.

➢ Assess why the processes above are important for the survival of a species.

Inquiry Question 3: Why is polypeptide synthesis important?

Content Descriptor: Construct appropriate representations to model and compare the

forms in which DNA exists in prokaryotes and eukaryotes: (5.3.1)

Prokaryotes DNA:

➢ Found in the nucleoid (non-membrane bound)

➢ Circular structure

➢ Non-compact

➢ Can also be found in plasmids

Eukaryote DNA:

➢ Found in the nucleus

➢ Linear structure

➢ Compact (compacted in histone proteins)

➢ Also found in mitochondria and chloroplasts

Content Descriptor: Model the process of polypeptide synthesis including:

Transcription and translation: (5.3.2)

Transcription:

1. Initiation – RNA polymerase moves along the double stranded DNA chain, separating the

chain.

2. Elongation – RNA polymerase adds the complementary RNA nucleotides reading 5’ ➔ 3’

3. Termination – Sequences known as terminators signal RNA transcript is complete.

4. mRNA strand moves through the nuclear envelope towards the ribosomes.

Translation:


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1. Free floating tRNA binds to specific amino acids in the cytoplasm.

2. tRNA is attracted into the ribosome, its anticodon binding with the corresponding codon to

the nucleic bases read on the mRNA.

3. tRNA deposits the amino acid.

4. Chain lengthens as more amino acids are deposited, joining together to make a polypeptide.

Assessing the importance of mRNA and tRNA in transcription and translation: (5.3.3)

tRNA and mRNA are vital in the transcription translation process. In transcription, the mRNA strand

forms from the template strand as read by RNA polymerase. This is then sent out through the nucleic

envelope towards the ribosomes. Without mRNA, the DNA code specifying the sequence of amino

acids would not form. Thus, mRNA is of vital importance to the transcription process, and for

polypeptide synthesis. In translation, tRNA is attracted into the ribosome to deposit their

corresponding amino acids onto the polypeptide chain. Without tRNA, the mRNA sequence could not

be converted into a distinct sequence of amino acids. Thus, tRNA is of vital importance to the

translation process and for polypeptide synthesis.

Analysing the function and importance of polypeptide synthesis: (5.3.4)

Polypeptide synthesis is the product of the transcription translation process. The deposited amino

acids form long chains; the specific charges of each amino acid dictating the folding and thus shape of

the polypeptide. This will affect its structure and therefore function of the polypeptide. Multiple

polypeptides join together to form proteins.

https://www.google.com.au/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=2ahUKEwjK_bSilpPjAhUHfH0KHZiVAMMQjRx6BAgBEAU&url=https%3A%2F%2Fwww.khanacademy.org%2Fscience%2Fbiology%2Fgene-expression-central-dogma%2Ftranscription-of-dna-into-rna%2Fa%2Foverview-of-transcription&psig=AOvVaw3rQ_aEILFaVmPu-LCZ0Ed0&ust=1562051705830057


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Assessing how genes and environment affect phenotypic expression: (5.3.5)

Phenotype:

The actual appearance of an organism, including all aspects of internal and external anatomy,

behaviour and physiology.

Genotype:

The genetic constitution of an organism, this can refer to a particular set of alleles in an organism. The

genome is the complete complement of an organism’s genetic information.

Genotype affects phenotype through the production of polypeptides. A gene is a section of DNA that

codes for a particular polypeptide, and when that gene is expressed, that section of the DNA molecule

is switched on, causing the polypeptide to be produced in the cell. These polypeptides are produced

through the processes of transcription and translation. These polypeptides which join together to form

proteins are essential in dictating cell function and thus the physiological and physical appearance of

an organism.

Environment:

Environment is the sum of all living and non-living surroundings. These conditions will affect that

appearance of an organism and the appearance of individual cells within the organism. This may be

due to the quality of nutrients and resources available to the organism or the amount of sunlight it

receives. These factors limit or accelerate the growth of certain aspects of the organism, affecting

phenotype. Phenotype may also be affected through the environment affecting genotype. Exposure to

certain environmental factors may cause mutations or cause certain genes to be switched on or off,

thus altering the phenotype of the organism. An example of this is a hydrangea.

Content descriptor: Investigate the structure and function of proteins in living things:

(5.3.6)

Protein:

The structure of protein can be divided into four sections. Primary, secondary, tertiary and quaternary.

Each section is ultimately caused by the coiling and compacting of the previous, with primary being

the specific bonds and sequence of amino acids.

Proteins have many roles. These include:

➢ Enzymes – Catalyse reactions allowing them to occur at a lower activation energy. These

include lactase.

➢ Structural – Fibrous protein such as collagen and keratin

➢ Transport – Channel proteins

➢ Storage – Ferritin

➢ Receptor – Guanine nucleotide-binding protein-coupled receptors (GPCRs)

➢ Antibodies – Immunoglobulins


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Globular proteins are spherical in shape and form colloids with water. Fibrous proteins are elongated

and form rods or wires.

Inquiry Question Review: Why is polypeptide synthesis important? (5.3.7)


➢ Describe the different forms of DNA in prokaryotes and eukaryotes.

➢ Explain transcription and translation and its biological significance.

➢ Describe the formation, structure and function of proteins.

Inquiry Question 4: How can the genetic similarities and differences within

and between species be compared?

Content Descriptor: Conduct practical investigation to predict the variation in the

genotype of offspring by modelling meiosis, including the crossing over of homologous

chromosomes, fertilisation and mutations: (5.4.1)

Method:

1. Prepare one or multiple pairs of chromosomes in homologous pairs. Note that these

chromosomes should be of similar size. Genes are denoted by a sentence, or alternatively

through the use of upper and lower case letters (showing dominant and recessive). Since this

is in prophase, each chromosome should be double-stranded.

2. Cut and remove one gene from one chromatid and exchange it with a gene from its

chromosome pair. This can happen independently across the two chromatid strands.

3. Continue process using the remainder of meiosis. Note that the daughter cells should not

contain the same genetic arrangement as the parent cell.


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Genetic variation:

Fertilisation – The mechanism by which meiosis and mutation act. The uniting of gametes allows for

the new assembly of alleles producing genetic variation. Mate selection can also impact which genes

are selected to be passed on.

Meiosis – Division into homologous pairs and crossing over re-arrange existing alleles into new

combinations creating genetic variation.

Mutation – Alterations in the genetic code causes changes to the amino acids which they code for.

This changes the amino acids produced, altering protein shape and therefore cell functioning. If this

mutation is in gametic cells, it may be passed onto offspring causing new alleles and thus genetic

variation from parents.

Content Descriptor: Model the formation of new combination of genotypes produced

during meiosis, including but not limited to:

Interpreting examples of autosomal, sex-linkage, co-dominance, incomplete dominance

and multiple alleles: (5.4.2)

Discrete genes: Distinct differences between gene expression such as blood type

Continuous genes: Spectrum of gene expression such as skin colour

Autosomal recessive:

➢ Males and females affected equally

➢ Can appear to skip generations

➢ Examples include cystic fibrosis, sickle cell anaemia

Autosomal dominant:


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➢ All affected individuals have affected parents

➢ Example includes Huntington’s disease

Sex (X) linked recessive:

➢ Males affected more frequently

➢ Appears to be passed from grandfather to grandchild

➢ Affected female’s sons will all be affected

➢ Haemophilia

Sex (X) linked dominant:


➢ All affected individuals have affected parents

➢ Affected father’s daughters will all be affected

➢ Rett syndrome

Incomplete dominance:

➢ Multiple alleles which appears as a blend of two other alleles. Neither allele is expressed over

the other, rather they are blended together, e.g curly, straight and wavy hair.

Co-dominance:

➢ New phenotype produced as both of the genes are expressed, e.g blood type in humans.


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Constructing and interpreting information and data from pedigrees and Punnett squares:

(5.4.3)

Pedigree:


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A pedigree should:

(a) Label the generation from the top down using roman numerals

(b) Label the individuals left to right using Arabic numerals. As much as possible, the leftmost

individual is the oldest, while the rightmost is the youngest. This may not always be possible

due to large scale pedigrees, however where siblings and partners are concerned from a single

descendent, this should be followed

(c) Use a key as shown above

Content Descriptor: Collect, record and present data to represent frequencies of some

characteristics in order to identify trends, patterns, relationships and limitation in data,

for example:

Examining frequency data: (5.4.4)

Sickle cell anaemia:

Group of diseases which affect haemoglobin, the molecule which carries and delivers oxygen to cells.

The disorder causes abnormal structure of haemoglobin, distorting red blood cells into a sickle shape.

Those with a single copy of the gene typically live normal lives without health problems resulting

from the condition.

It currently affects approximately 100,000 Americans. It is most common among those of African

ancestry, occurring in 1/500 African Americans and 1/1000 Hispanic Americans. The sickle cell gene

is carried by 1/12 African Americans and occurs in about 1/365 births

The pattern of data shows incidence higher for those of African descent. This is suspected to be

because a single sickle cell gene offers slight resistant to malaria, conferring an evolutionary

advantage where malaria is particularly common.

Analysing single nucleotide polymorphism (SNP): (5.4.5)

A SNP is a variation in a single base pair occurring at a specific locus on the genome. They are the

most common type of genetic variation; must occur in at least 1% of the population. They usually

occur during DNA replication. Since SNPs may be inherited from parents, they can be used to track

family disease and family history.


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➢ SNPS occur in 1/300 bases

➢ Approximately 10 million SNPS in the genome

Effects:

➢ If occurring at introns they do not lead to phenotypically expressed changes.

➢ However, if occurring in exons, they can cause issues in health.

➢ Some SNPs have been shown to lower risk from Alzheimer’s or prostate cancer

Inquiry Question Review: How can the genetic similarities and differences within and

between species be compared? (5.4.6)


➢ Describe a method to model meiosis

➢ Understand the implications of different types of inheritance and gene expression

➢ Be able to interpret pedigrees and Punnet squares

➢ Understand SNPs

Inquiry Question 5: Can population genetic patterns be predicted with any

accuracy?

Content Descriptor: Investigate the use of technologies to determine inheritance

patterns in a population using, for example:

DNA sequencing and profiling: (5.5.1)

DNA profiling (fingerprinting):

Involves determining the identity of an individual. It does not determine the genome or sequence of a

DNA molecule.

1. DNA is extracted and purified.

2. DNA is cut using a restriction enzyme.

3. DNA replicated using polymerase chain reaction

4. Electrophoresis separates the STR based on length

5. Stained with radioactive dyes.

Used in paternity cases, identifying bodes and diagnosing inherited disorders. Restriction enzymes cut

DNA along specific restriction sites. Polymorphisms (SNPs) at these sites can inactivate the

restriction site, causing the unique fingerprint of each individual in the species.

DNA sequencing:

Determining the exact order of nucleotides in a DNA molecule.

1. DNA is purified and extracted.

2. Genome is replicated using enzymes

3. Nucleic bases are stained

4. Gene sequencing machine analyses date to produce genome sequence (this may involve

electrophoresis)

Used for determining evolution patterns, identifying phenotypic issues with SNPS


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Content Descriptor: Investigate the use of data analysis from a large-scale collaborative

project to identify trends, patters and relationships, for example:

The use of population genetics data in conservation management: (5.5.2)

Conservation Management:

Population genetics data can be used to identify issues with endangered animals. Sampling of

differences across the population can be used to determine the size of the gene pool. One example of

this is the endangered mountain Pygmy-possum. Genetics testing showed that they had an extremely

small gene pool in each of the isolated populations. This lack of genetic diversity likely means that a

small population would be unable to adapt to climate change. Populations from mount Kosciusko

were crossbred with those from mount Bulla. This example of genetic flow helped to increase the

biodiversity of the population.

Another example is the Tasmanian Devil. Study of SNPS showed that Tasmanian devils have very

little genetic diversity. This meant many of them had a predisposition to not fight the fatal DFTD. In

2017 scientists found a way to force the expression of genes which fight the cancer.

Population genetics studies used to determine the inheritance of a disease or disorder:

(5.5.3)

In Australia, all babies are screened for phenylketonuria (PKU). Other screening programs test for

Fragile X syndrome. Testing can be performed on newborns, mothers or parents to determine if they

are a carrier.

An example of a disease which is tested for is Huntingtin’s. This disease causes brain degeneration

and loss of cognitive function, with an international prevalence of approximately 0.006%. It is

dominant, and can be screened for; however, data analysis shows that 10% of cases involve new

mutations and are not related to inheritance. Sequencing for the number of HD alleles can determine if

an individual may or may not develop Huntingtins (less than 35 repeats will not develop 40 or more

will develop).

Population genetics relating to human evolution: (5.5.4)

Humans are classified as a primate. There are genetic variations between human populations and

individuals within a population. The 1000 Genomes Project started in 2008 as an international

research to catalogue human genetic variations and changes in human evolution and predisposition to

disease.

Study of mtRNA (mitochondrial DNA) has been used to support the ‘Out of Africa’ model of human

migration, suggesting that there have been multiple migrations, with all present humans descending

from a single group.

Inquiry Question Review: How can the genetic similarities and differences within and

between species be compared? (5.5.5)


➢ Describe and compare DNA fingerprinting and sequencing

➢ Give examples for the use of genetic technologies in a variety of areas


32


33

Module 6: Genetic Change

Inquiry Question 1: How does mutation introduce new alleles into a

population?

Content Descriptor: Explain how a range of mutagens operate, including but not

limited to:

Electromagnetic radiation sources (6.1.1)

Physical (electromagnetic radiation sources)

➢ Ionising – Radioactive material which is highly ionising such as radioactive waste, causes

backbone or pairs to break

➢ UV radiation – Some UV can disrupt bonding or cause the formation of a thymine dimer.

➢ Excessive heat – Vibrate and break apart

Chemicals (6.1.2)

Chemical (may be base analogues fit into the place of a base, or intercalating agents which stick in

between bases)

➢ Ingested – Tar, alcohol and fatty foods, adds bulky chemicals which interfere with replication.

➢ Irritants and poisons – Benzene and cleaning products

➢ Metal pollutants – Mercury, arsenic, cadmium causes the formation of reactive oxygen

sequences.

Naturally occurring mutagens (6.1.3)

Biological (naturally occurring mutagens)

➢ Transposons – Autonomous relocation and gene disruption

➢ Viruses – Change gene function, cause damage through inflammation.

Content Descriptor: Compare the causes, processes and effects of different types of

mutation, including but not limited to:

Point mutation (6.1.4)

Point mutations refer to mutations to a single nucleic base pair.

➢ Substitution – Single base pairs are mutated into a different pair. When this occurs in all cells

in the individual, it is referred to as a SNPS. These can occur during DNA replication, due to

a mutagen or a copying error. Usually has a low impact upon the individual, as it will only

affect a single amino acid. Example diseases caused by substitution includes sickle cell

anaemia.

➢ Deletion or insertion (frameshift) – The addition or removal of a single nucleic base pair. This

can be caused by intercalating mutagens. Shifts the codon reading frame to vastly alter

phenotypic expression. Examples of diseases caused by this includes cystic fibrosis.


34

Changes caused by a point mutation can be:

➢ Silent – Substitution caused no change to amino acid produced and thus has no phenotypic

expression.

➢ Missense – Mutation causes the incorrect amino acid to be produced and added to

polypeptide. This will affect phenotypic expression as the incorrect protein will be produced

which will alter the cells’ physiology.

➢ Nonsense – Mutation prematurely places a stop codon, making the polypeptide undeveloped

and non-functioning.

Chromosomal mutation (6.1.5)

Sectional changes:

Refers to a mutation of the sections of genes on the chromosomes. These mutations only occur during

meiosis:

➢ Deletion – Segment of DNA is lost on chromosome. Will affect phenotypic expression since

genetic information is not present.

➢ Inversion – Section of DNA is inverted to be arranged in the opposite direction. Usually will

not have a large effect on genetic information since no genetic information is lost.

➢ Translocation – Sections of DNA are placed onto a different non-homologous chromosome.

This will cause the gametes to either have more or less genetic information.

➢ Duplication – Segment lost from one chromosome and added onto its’ homologous pair.

Similar to translocation, this will cause the gametes to either have more or less genetic

information.

Aneuploidy:

The condition of having more or fewer chromosomes than the standard number (2N+1, 2N+2,2N-

1…). This usually results from the non-disjunction of chromosomes during anaphase I or II during

meiosis.

Down Syndrome (trisomy 21):

A form of polysomy (greater number of chromosomes than standard), caused by an additional

chromosome 21. Down Syndrome can be caused by:


35

➢ Non-disjunction of chromosome 21 in meiosis. This accounts for 95% of Down Syndrome

cases.

➢ Translocation of chromosome 21, attaching itself to another chromosome, usually

chromosome 14. This accounts for 3% of cases.

➢ Miotic errors – The failure of the pair of chromosomes 21 to separate during early embryonic

miotic divisions. This accounts for under 3% of cases.

Down Syndrome occurs in approximately 1/800 births of women aged 30-31, increasing drastically as

the maternal age increases, due to the high rate of mutation in eggs.

Characteristics of Down Syndrome include:

➢ Intellectual disability

➢ Characteristic physical features such as poor muscle tone

➢ Difficulty with speech and communication

Content Descriptor: Distinguish between somatic mutations and germ-line mutations

and their effect on an organism: (6.1.6)

Germline:

➢ Occur in sex cells or the production organs for sex cells, caused by the exposure of these cells

to mutagens.

➢ Will be passed onto offspring who receive mutated gametes.

➢ Will affect localised cells but may also impact a community through offspring.

Somatic:

➢ Occur in a regular body cell. Caused by exposure to a mutagen, this mutation will be

expressed in any cells which are produced via mitosis as clones of the affected cell.

Uncontrolled replication of cells affected by somatic mutations are cancers.

➢ Cannot be passed onto offspring.

➢ Effect will be localised, impacting the functioning of the cells affected and possibly the

individual if the mutation is widespread.

Cancer:

Normal cells are programmed to die in a process called apoptosis, usually corresponding with the time

that they have accumulated damage which prevents them from carrying out their normal function.

Cancer cells have mutated such that their regulatory genes have been switched off, allowing them to

continue to replicate regardless of the damage they have accumulated.

Content Descriptor: Assess the significance of ‘coding’ and ‘non-coding’ DNA segments

in the process of mutation: (6.1.7)

Coding:

Coding segments of DNA hold the information which is changed into amino acids and proteins

through the process of transcription translation. Mutations in these coding regions will therefore affect

the proteins produced if the mutation is nonsense of missense. This will thus be phenotypically

expressed through affecting cell processes and function.

Non-coding:

While non-coding sections do not code for proteins, mutations in these non-coding regions have been

shown to affect regulatory proteins and the expression of genes. Thus, non-coding regions will also

indirectly be expressed.


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Content Descriptor: Investigate the causes of genetic variation relation to the processes

of fertilisation, meiosis and mutation: (6.1.8)

Mutation:

Alterations in the genetic code causes changes to the amino acids which they code for. This changes

the amino acids produced, altering protein shape and therefore cell functioning. If this mutation is in

gametic cells, it may be passed onto offspring causing new alleles and thus genetic variation from

parents.

Meiosis:

Division into homologous pairs and crossing over re-arrange existing alleles into new combinations

creating genetic variation.

Fertilisation:

the mechanism by which meiosis and mutation act. The uniting of gametes allows for the new

assembly of alleles producing genetic variation. Mate selection can also impact which genes are

selected to be passed on.

Content Descriptor: Evaluate the effect of mutation, gene flow and genetic drift on the

gene pool of populations: (6.1.9)

Effect on gene pool:

➢ Mutation – Acts via the mechanism of natural selection. Provides random mutations which

may be beneficial to the survival of the organism making it more likely to be passed onto

offspring. Increases genetic diversity.

➢ Gene flow – Migration from one place to another, causes an increase or decrease in genetic

diversity due to the loss or gain of different allele frequencies. For example, sickle cell has a

frequency of 0.1 in Sudan but a 0.01 frequency in Australia. A large migration from Sudan to

Australia would alter the gene pool by increasing the sickle cell gene frequency.

➢ Genetic drift – Random events which cause an allele frequency. This may be due to a weather

event such as storm (known as bottleneck) or a small sample of the population moves to a

new area, not fully representing the old population (the founder effect). Genetic drift can

cause alleles to become fixed (100% frequency) or lost (0%) frequency. Tends to reduce

genetic diversity.

Hardy Weinberg Equilibrium:

Where P and Q represent a dominant and recessive allele:

𝑃2 + 2𝑃𝑄 + 𝑄2 = 1

𝑃 + 𝑄 = 1


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Inquiry Question Review: How does mutation introduce new alleles into a population?

(6.1.10)


➢ Describe the different types of mutagens and how the operate

➢ Understand the process and effects of:

o Germline mutation

o Somatic mutation

o Mutation in coding and non-coding regions

o Gene flow

o Genetic drift

➢ Compare chromosomal and point mutations

Inquiry Question 2: How do genetic techniques affect Earth’s biodiversity?

Content Descriptor: Investigate the uses and applications of biotechnology (past,

present and future), including:

Analysing the social implications and ethical uses of biotechnology, including plant and

animal examples (6.2.1)

Biotechnology definition:

Biotechnology is the harnessing and exploitation of cellular, biomolecular and living processes for

industrial and other purposes.

Past uses of biotechnology:

Fermentation of wine was believed to have originated 7,000 years ago with damaged grapes

accidentally fermenting. Early farmers enjoyed the taste of the juice compared to that unfermented. In

1891 Hermann Muller demonstrated that bacteria were responsible for types of fermentation in wine.

Fermentation of wine is a result of yeast microorganisms converting sugar into ethanol and carbon

dioxide. Through this process the microbes use at least 12 core enzymes. Variations can be made to

the process to achieve a variety of different flavours; these variations include length of fermentation

and type of sugar.

Other past examples include the fermentation of cheese and animal husbandry.

Present uses of biotechnology:

➢ Fermentation and industrial processes such as the production of ethanol

➢ DNA Profiling – identification of a specific and unique pattern in DNA. Involves extraction,

replication, electrophoresis through gel to separate the different lengths of STR (short tandem

repeats) and identification using fluorescent labelling. For more information see (5.5.1)

➢ Recombinant DNA cloning – pasting a DNA section into a vector which then clones it, such

as a bacteria plasmid. These bacteria are then selected using antibiotics which are then used

for research. This can be used for investigating function or mutations as well as characteristics

of genes.

Future uses of biotechnology:

Treatment for cystic fibrosis – caused by a mutation in the CFTR gene leading to lack of the

mediating enzyme. Causes lung infection and persistent coughing and phlegm. Research is being done

into the incorporation of correct copies of the genes into lung cells. This may be through a hybrid

virus, one of the natural forms of mutations in cells.


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Biotechnology – Case Study A – Aqu Advantage Salmon

➢ GMO (genetically modified organism) developed in North America. Alters the genes of

Atlantic salmon to include the genes from Chinook salmon, allowing them to grow twice as

fast when compared to unmodified salmon while also consuming less food.

➢ Social considerations – Pose a perceived threat to the livelihood of wild salmon fishers. This

is exemplified in Alaska, where the industry employs 60,000 people. Farming of these salmon

is expected to out-compete the natural fishing.

➢ Economic – Aqu Advantage salmon are economically more viable than traditional salmon

fishing, being able to control production of fish in much larger quantities for fractions of the

price. This also may reduce transport costs due to inland fish farms. Furthermore, these farms

would be able to increase growth in the fishing sector.

➢ Cultural – Issues with the labelling and ethical concerns regarding consuming GMO.

Consumer awareness can be ensured through labelling laws.

➢ Environmental – Agricultural use of these GMO salmon poses a threat to a variety of fish and

ecosystems should they escape from farms. They may be able to outcompete similar fish in

ecological niches, which has implications for biodiversity of entire food webs.

Biotechnology – Case Study B – Bt Cotton

➢ Project designed to increase the efficiency of the cotton crop. Refers to a group of proteins

from the Bacillus thuringiensis strain of bacteria. The genes that code for these proteins are

added to the cotton, causing them to secrete toxins which kill insects which feed on them.

➢ Social considerations – Bt cotton seeds are highly restricted causing farmers to become

dependent on their sale making them vulnerable to market changes. Likewise, those which

cannot afford to change seeds in developing nations may be outcompeted.

➢ Economic – Bt cotton is far more economically viable than traditional cotton, decreasing cost

of pesticides by 93% in Australia since its introduction in 1997. Bt cotton also has reduced

water usage (3-4% lower), which can be costly in rural areas.

➢ Cultural – Ethical debate over introduction in developing nations after the instance in India,

one of the world’s largest cotton producers. After its introduction in 2003, a crop failure led to

farmers being unable to pay back loans for the seeds, leading to large reported suicides

between 2004-2006.

➢ Environmental – As a plant that requires cultivation there is little chance of outcompeting

native plants. While the increased efficiency does reduce land used, it is still supporting

agricultural waste from the fashion industry.

Researching future directions of the use of biotechnology: (6.2.2)

Areas of research:

➢ Treatment of non-infectious disease through altering genome.

➢ Control of infectious diseases such as malaria through altering mosquitos so they are

inhospitable to the protozoan.

➢ Research into the cause and treatment of non-infectious disease through study of the human

genome and non-coding regions.

➢ Treatment of cancer and disease through stem cell research.

Cystic fibrosis treatment:

Cystic fibrosis (CF) is caused by a frameshift mutation, causing cells to not produce an enzyme which

mediates the conditions in normal humans.

A large area of research is currently dedicated to using biotechnology to reverse the mutation of the

CFTR gene. To achieve this reversal, correct pieces of DNA need to be delivered to individual cells.


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From there, either the cell incorporated the correct version of the CFTR gene (integrating gene

therapy), or it temporarily uses an attached copy (non- integrating gene therapy). While trials in mice

have been promising, the appropriate method of delivery of the genes still requires further research.

One method currently under investigation is through attachment to a hybrid virus, which delivers the

DNA.

The benefit of genetic treatments for CF is that it will likely be effective for any mutation of the

CFTR gene and therefore useable by all CF patients.

Other areas of research include non-genetic treatments, such as the development of anti-inflammatory

micro-molecules which block multiple of the enzymes involved in inflammation.

Evaluating the potential benefits for society of research using genetic technologies: (6.2.3)

Stem cell research:

Stem cell research is the exploitation of the pluripotent embryonic cells. Under correct conditions,

these cells can be manipulated to become other stem cells or differentiated functional cells. This has a

variety of applications such as:

➢ Understanding how diseases occur and develop through observing the maturity of stem cells

➢ Regenerating damage cells and tissues caused by a variety of conditions

➢ Testing drug treatment effectiveness

Stem cells can be sourced from embryonic cells or from stem cells in adult bone and fat tissue. There

has been some controversy over the use of embryonic cells for research, regarding the living state of

the embryo.

Benefit of stem cell research:

Stem cells could provide a significant benefit to society. Further research could allow stem cells to be

used instead of organ transplants, both improving access to healthy organs and significant quality of

life. They may also be used in treatment of cancers and blood disease. This will likely help to improve

overall quality of life for humans.

While genetic technologies such as stem cell research have significant potential to improve society,

there may be unforeseen factors, such as adverse responses to treatments.

Evaluating the changes to Earth’s biodiversity due to genetic techniques: (6.2.4)

Impact on biodiversity:

Genetically modified organisms whether plant or animal will be able to outcompete their unmodified

counterparts. A prime example of this is in transgenic sunflowers, which are capable of producing

50% more seeds than unmodified plants. This advantage, as well as more efficient use of resources is

feared to cause non-GMO sunflowers to be outcompeted for resources such as land, thus harming

biodiversity. There are also possible negative impacts for the existence of entire species, as can be

found in the example of AquAdvantage salmon. The creation of these salmon through genetic

technologies pose a threat to the biodiversity of a variety of fish and ecosystems, should they escape.

These salmon if released could outcompete similar fish in their ecological niche, which has further

implications for entire food webs which may rely upon these species for food.

While genetic technologies such as AI may encourage the reduction of genetic diversity through

promoting limited alleles, it also enables the uniting of different genetic combinations from vast areas,

overcoming geographical barriers. These methods also may promote biodiversity through the increase

in genetic diversity, such as the creation of hybrids.


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Inquiry Question Review: How does mutation introduce new alleles into a population?

(6.2.5)


➢ Describe multiple examples of biotechnology

➢ Evaluate the overall impact and benefit of various genetic technologies

Inquiry Question 3: Does artificial manipulation of DNA have the potential

to change populations forever?

Content Descriptor: Investigate the uses and advantages of current genetic technologies

that induce genetic change: (6.3.1)

AquAdvantage salmon:

Benefits:

➢ More efficient food production reduces impact of overfishing

➢ Cheaper food to produce

➢ Increases biodiversity through the production of hybrids

➢ Inland farms can increase access of landlocked regions to fish

Disadvantages:

➢ May damage ecosystems if salmon escape

➢ Using inland regions can lock down water which may be necessary for human use

➢ Remove job opportunities from outcompeted fishermen

➢ Contribute to the eutrophication of waterways

Recombinant production of insulin:

Benefits:

➢ Allows increased and cheaper production of insulin for those suffering from diabetes

➢ Led to breakthroughs in the areas of recombinant DNA research

Content Descriptor: Compare the processes and outcomes of reproductive technologies,

including but not limited to:

Artificial insemination: (6.3.2)

Artificial pollination: (6.3.3)

Comparison:


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Content Descriptor: Investigate and assess the effectiveness of cloning, including but not

limited to:

Whole organism cloning: (6.3.4)

Organism cloning:

Whole organism clones can be made through asexual methods, such as those in bacteria, plants and

fungi. Clones can also occur in identical twins when an egg splits in utero.

Cloning of organisms can be artificially induced:

1. Unfertilized egg has nucleus removed

2. Skin cells from adult are fused with egg using an electric pulse

3. Cell division

4. Implanted into surrogate mother

Many organisms have been cloned using somatic cells, including sheep, cows, cats, dogs and rabbits.

While successful trials have occurred, they often have a lower life expectancy.

Gene cloning: (6.3.5)

Gene cloning:

Gene cloning is completed through use of recombinant DNA

1. DNA is extracted from an organism

Technology Method Impact on population

Artificial

insemination

Semen is harvested from bulls. This semen is

injected using a syringe into vagina of a

female cow, timed with menstrual cycles to

ensure highest chance of success. Mates are

chosen to produce desirable offspring

Produces offspring with desirable

characteristics such as higher meat quantity.

Tends to reduce biodiversity which may

make population more susceptible to

disease. May also increase bio-diversity

through uniting geographically separated

gametes

Artificial

pollination

Pollen from selected plants is collected on the

stamen of male flowers, while the undesirable

plants have their stamen removed by

trimming. This pollen is delivered manually

such as via paintbrush to the stigma of female

plants. Mating plants are chosen to produce

desirable characteristics.

Produces offspring with desirable

characteristics such as smaller seeds. May

reduce biodiversity, however plants can

easily incorporate foreign aspects of genome

into their own. May also increase bio-

diversity through uniting geographically

separated gametes.


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2. DNA is introduced to restriction enzymes which select single genes of interest which they

cut away

3. Cut away DNA is introduced into plasmids, which combine it into their genome

(recombinant)

4. DNA is transferred into bacteria using chemical methods

5. Bacterium are grown in colonies

6. Colony which holds the desired genes is selected and cultured

Content Descriptor: Describe techniques and applications used in recombinant DNA

technology, for example:

The development of transgenic organisms in agricultural and medical applications: (6.3.6)

Recombinant DNA:

Allows for multiple copies of genes to be made and thus inserted into other organisms go give new

traits. Traits may include disease resistance or a different colour, refer also to case studies A and B

(6.2.1)

➢ Agriculture – Used to make more efficient, cost effective and resilient organisms. This is

done through the production of transgenic organisms (Case studies A and B).

➢ Medicine – Tests done on copies of genes to determine risk factors for non-infectious genetic

disease. Also used in the production of vaccines and proteins such as insulin, interferons and

human growth hormone.

Content Descriptor: Evaluate the benefits of using genetic technologies in agricultural,

medical and industrial applications: (6.3.7)

Evaluation:

➢ Agriculture – Significant impact on increasing food production (Case studies A and B)

(6.2.1).

➢ Medicine – Can be used to increase quality of life for humans, generally the benefits and

possible improvements significantly outweigh the ethical or unforeseen consequences.

➢ Industry – Genetic technologies such as recombinant DNA is used for the industrial

production of proteins, usually used in the pharmaceutical industry. This both increases the

benefit to human health, but also significantly decreases the cost of pharmaceuticals. While

this cost is reduced, the benefit is not always passed onto the consumer. Genetic technologies

have also been used to produce biofuels through altering the waste product of target bacteria.

Content Descriptor: Evaluate the effect on biodiversity of using biotechnology in

agriculture: (6.3.8)

Evaluation: (From 6.2.4)

Genetically modified organisms whether plant or animal will be able to outcompete their unmodified

counterparts. A prime example of this is in transgenic sunflowers, which are capable of producing

50% more seeds than unmodified plants. This advantage, as well as more efficient use of resources is

feared to cause non-GMO sunflowers to be outcompeted for resources such as land, thus harming

biodiversity. There are also possible negative impacts for the existence of entire species, as can be

found in the example of AquAdvantage salmon. The creation of these salmon through genetic

technologies pose a threat to the biodiversity of a variety of fish and ecosystems, should they escape.

These salmon if released could outcompete similar fish in their ecological niche, which has further

implications for entire food webs which may rely upon these species for food.


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While genetic technologies such as AI may encourage the reduction of genetic diversity through

promoting limited alleles, it also enables the uniting of different genetic combinations from vast areas,

overcoming geographical barriers. These methods also may promote biodiversity through the increase

in genetic diversity, such as the creation of hybrids.

Content Descriptor: Interpret a range of secondary sources to assess the influence of

social, economic and cultural contexts on a range of biotechnologies: (6.3.9)

Social:

Case study A One major social consideration supporting the introduction of Bt cotton is simply the

huge demand for cotton as a product of over 28 million tons in 2018. Bt cotton is far more efficient

for land use; in Australia in 2012 it produced $180/hectare more worth of cotton and Bt cotton usage

worldwide has seen 50% more cotton grown on the same amount of land than that of 40 years ago. Bt

cotton is also more water efficient, consuming 3-4% less water than regular plants. Therefore, use of

Bt cotton provides more arable land and available water for other uses such as food production.

However, use of Bt cotton may also cause large amounts of competition which may lower the price

and thus wages for farmers selling cotton. This also has implications for ethical considerations.

Overall biotechnologies have significant benefit to society. These benefits should be considered with

reference to the possible threat which biotechnology poses.

Economic:

Generally, economic factors favour the use of biotechnology. Biotechnology enables the cheaper

production of food, medicine and industry. Recently, this has enabled private companies to pursue the

exploitation of genetic technologies.

Cultural:

As referenced in 6.2.3, there is some cultural and religious controversy regarding the use of

biotechnology. Cultural demand for goods such as cotton has also influenced the integration of a

variety of genetic technologies.

Inquiry Question Review: Does artificial manipulation of DNA have the potential to

change populations forever? (6.3.10)


➢ Describe and compare the impacts of artificial insemination and pollination

➢ Assess the effectiveness of cloning

➢ Maintain a vast knowledge of multiple case studies of genetic technologies in order to

evaluate their impacts and benefits


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Module 7: Infectious Disease

Inquiry Question 1: How are diseases transmitted?

Content Descriptor: Describe a variety of infectious diseases caused by pathogens,

including microorganisms and macroorganisms and non-cellular pathogens, and collect

primary and secondary sourced data and information relating to disease transmission,

including:

Classifying different pathogens that cause disease in plants and animals (7.1.1)

Classification table:

Pathogen Disease example Size Genetic Material

Macro-parasites Tape-worm

infestation

Can be seen with

naked eye

Multicellular

eukaryotes

Protozoan Malaria 1 - 50 µm Single celled

eukaryotes

Fungi Athlete’s foot, tinea 2 – 10 µm Single celled or

multicellular

eukaryotes

Bacteria Cholera, anthrax 0.5 – 5 µm Single celled

prokaryotes

Virus Influenza, ebola 20 – 400 nm Acellular DNA or

RNA in a protein coat

Prion Mad cow disease

(BSE)

Smallest pathogen 1-

10 nm

Misfolded protein

which contains no

genetic code

Investigating the transmission of a disease during an epidemic: (7.1.2)

Ebola:

Ebola is transmitted through bodily fluids or through close bodily contact. Ebola’s suspected natural

reservoir is in bats and is transmitted to humans through uncooked bat meat. Significant factors which

have impacted the spread of Ebola in Africa include:

➢ Tradition of manual handling of remains of the deceased

➢ Tradition of burning the body of the deceased

➢ Poor general sanitation, i.e handwashing

Design and conduct a practical investigation relation to the microbial testing of water or

food samples: (7.1.3)

Investigation to test for microbes in food:

1. Prepare two agar plates with nutrient jelly.

2. Contaminate a Q-tip with the tested food source

3. Inoculate the first plate with the contaminated Q-tip, ensuring it is only briefly exposed to air

4. Briefly expose the second agar plate to air

5. Incubate both agar plates for three days


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6. Compare the number of colonies and approximate area of the contaminated plate with the

control

Investigate modes of transmission of infectious diseases, including direct contact, indirect

contact and vector transmission: (7.1.4)

Direct contact:

➢ Spread directly from one person to another. This can be by close contact, or bodily fluids.

➢ HIV is an example of a disease spread through direct contact (intercourse).

Indirect contact:

➢ Spread not through direct contact, for example through air, ground, soil or contaminated

articles.

➢ Cholera is an example of a disease spread through indirect contact. Measles can be spread

through direct or indirect contact.

Insect vector:

➢ Transmission from one person to another via an infected animal.

➢ Mosquitoes are the insect vector for the protozoan disease malaria.

Communicability of a disease depends on how easily it leaves a host and enters another person. The

most communicable diseases are easily passed from one person to another.

Content Descriptor: Investigate the work of Robert Koch and Louis Pasteur, to explain

the causes and transmission of infectious disease, including:

Koch’s postulates: (7.1.5)

Contributions of Koch:

German physician who took his medical degree in 1866. Upon moving to a county where the

livestock were greatly affected by anthrax, and learning of Pasteur’s evidence for germ theory, Koch

discovered the cause of anthrax to be Bacillus anthracis.

In 1877 Koch described new techniques of fixing and staining bacteria. He used dye to stain the

bacteria and solid gels to isolate them rather than sticky liquids.

In 1884 he made the list of criteria to prove that an organism causes a set disease; Koch’s postulates.

In 1891 he found the agents that cause diphtheria, typhoid, tetanus and tuberculosis. In 1905 he

developed the tuberculin test for tuberculosis.

Koch’s postulates:

Koch’s postulates are a method of linking a set disease to a set disease causing pathogen:

1. Organism must be present in every diseased individual

2. The organism must be able to be isolated and grown in pure culture

3. Pure cultures must induce disease when given to another organism


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4. The same microbe must be able to be isolated, cultured and identified as the original species

Pasteur’s experiments on microbial contamination (7.1.6)

Contributions of Pasteur:

Pasteur was originally a chemistry teacher, until one of his student parents asked him to help with

problems with spoiling wine in 1856. Pasteur proved that yeast was the cause of normal fermentation,

rather than “unstable vibrations” and that the cause of the souring of wine was contamination by

micro-organisms.

Further studies showed organisms caused fermentation of wine, beer and vinegar. He suggested

heating the liquids to moderate temperatures to kill the microbes and then adding the desired

organisms. In the 1860’s he conducted his experiment on the swan neck flasks, disproving

spontaneous generation and with his work on anthrax, he developed the germ theory.

After isolating and diluting infected sheep’s blood, he found that anthrax was just as active as the

original. He produced a vaccine for anthrax in 1882 which was publicly tested, educating the public

about vaccination.

Pasteur’s experiment:

Method:

1. Fill two long neck flasks with nutrient broth.

2. Heat and bend one of the flask necks into a swan neck

3. Boil both broths to kill any microbes

4. Leave for a number of days

5. Examine the colour of each broth


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Other modifications to his experiment included snapping the neck off the bent flask once finished or

pouring the condensation which trapped dirt back into the flask.

Both broths were composed the same, and both were boiled so no microbes were present. The broth

that was exposed to the environment spoiled, while the broth which was not exposed did not.

However, the swan neck flask still allowed air to diffuse through the layer of water in the neck while

trapping microbes. Since the flask still had access to air, the germs did not simply appear, they had to

come from somewhere in the environment.

Content Descriptor: Assess the causes and effects of diseases on agricultural production,

including but not limited to:

Plant diseases: (7.1.7)

Citrus canker:

➢ Caused by bacterium Xanthomonas citri

➢ Forms lesions on stems, leaves and fruit

➢ Notifiable disease – if found must be reported to authorities

➢ Outbreak in 2005 had high economic impact

➢ Australia was declared free of citrus canker in 2009

Wheat rusts:

➢ Caused by several species of fungi

➢ Cause damage to various parts of plants

➢ Spread by spores

➢ Controlled via fungicides and resistant strains

Potato moth:

➢ Destructive pest of potatoes

➢ Caterpillar feeds on the leaves and tubers

➢ Insecticides kill caterpillars

Karnal bunt of wheat:

➢ Notifiable fungal disease

➢ Attacks flowers and invades what kernels

➢ Highly invasive and threat to wheat industry

➢ Molecular probes can detect spores

➢ Significant cost of identification and restriction

Animal diseases: (7.1.8)

Internal parasites:

➢ Roundworms and flatworms affect agricultural animals reducing productivity and causing

higher mortalities

Anthrax:

➢ Bacterial infection caused by Bacillus anthracis

➢ Affects many species of livestock and humans

➢ Notifiable disease – if found must be reported to authorities

➢ Can survive in alkaline soil, infecting animals once they are exposed

➢ Blood tests can identify

➢ Antibiotics useful in early stages


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➢ Related costs include:

• Disposal of infected carcasses

• Animal death

• Treatment

• Vaccination

• Consumer rejection

ABLV:

➢ Australian Bat lyssavirus

➢ Related to rabies, transferred through bites

➢ Causes seizers and inflammation

➢ Present in all bat populations

➢ Affected no agriculture

Flystrike:

➢ Caused by species of blowflies

➢ Affect Australian sheep

➢ Lay eggs in sheep, maggots eating tissue causes wounds and attracting more flies

➢ Prevention includes:

• Removing tails

• Shearing and chemical treatments

➢ High economic impact and decreased productivity

Content Descriptor: Compare the adaptations of different pathogens that facilitate

entry into and transmission between hosts: (7.1.9)

Complex life cycles:

➢ Many pathogens live in multiple hosts

➢ The host of sexual reproduction is called the primary host

➢ The host of asexual reproduction is the secondary or intermediate host

➢ Complex life cycles take advantage of an aspect of the host:

• Malaria is carried by the insect vector Anpheles mosquito

• Yersinia pestis which causes bubonic plague blocks the digestive tracts of fleas, forcing

them to vomit to remove the blockage

Attachment structures:

➢ Bacteria have adhesion proteins to help them bind to surfaces

➢ Adhesion structures include fimbriae (short) and pili (long)

Active transport:

➢ Viruses bind to receptors triggering endocytosis into cells

Resistant structures:

➢ Structures which help them live outside the host

➢ Endospores are tough and extremely resistant spores which survive outside of hosts. An

example of this is anthrax

➢ Virus outside of host is called virion, some viruses cannot survive for long, such as HIV

➢ Viral envelopes help the virus avoid the host immune system, however it often means they are

not very virulent outside of the body


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Inquiry Question Review: How are diseases transmitted? (7.1.10)


➢ Describe a variety of diseases and how they spread

➢ Understand the process to test for microbial contamination through experimental methods

➢ Describe and assess the scientific importance of the work of Koch and Pasteur

Inquiry Question 2: How does a plant or animal respond to infection?

Content Descriptor: Investigate the response of a named Australian plant to a named

pathogen through practical and/or secondary-sourced investigation, for example:

Fungal pathogens: (7.2.1)

Waratah:

The waratah is a native Australian plant, with characteristic bright red flowers. It uses these flowers

and large quantities of nectar, attracting birds and pollinators. The curved shape of the individual

flower’s brushes honey eaters with nectar, with its seeds also being dispersed by birds. Adaptations to

the environment include:

➢ Lignotubers which can re-sprout after bushfires

➢ Thick waxy leaves

Fungal pathogens:

➢ Damping off refers to the fungal infection of the root and crown

➢ One fungal pathogen is Phytophtora cinnamomi

➢ Symptoms include:

• Yellow leaves

• Wilting

• Dieback

• Blackening and death of stem and roots

➢ This can be artificially prevented by the use of fungicides

Waratah response:

➢ Secretion of anti-fungal enzymes making an inhospitable environment for fungi

➢ Jettison infected leaves or stems

➢ Strengthening of cell wall to deter further penetration

Viral pathogens: (7.2.2)

Bananas:

A large flowering plant which has been genetically bred so that no bananas have seeds. Bananas now

reproduce via asexual methods

Viral pathogens:

➢ BBTV (banana bunchy top virus) is a single stranded viral pathogen transmitted by the insect

vector of aphids.

➢ This causes stunted leaf growth:

➢ Artificial control measures include control of the aphid vector

Banana response:


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➢ A technique known as RNA silencing is employed by plants, where plants recognize the viral

genetic material and copy it so other cells can respond to the virus

Content Descriptor: Analyse responses to the presence of pathogens by assessing the

physical and chemical changes that occur in the host animal’s cells and tissues: (7.2.3)

Physical Changes:

Inflammation and its subsequent signs, caused by chemical responses to the pathogen:

➢ Redness

➢ Swelling

➢ Loss of function

➢ Pain

➢ Heat

Chemical changes:

➢ Some intracellular bacteria take over protein synthesis

➢ Apoptosis (cell death) to seal off a pathogen

➢ Infected cells release cytokines and chemokines, which stimulate lymphocytes and

chemotaxis

➢ Interferons stimulate the release of antivirals

➢ Series of chemicals which cause inflammation:

• Heparin – prevents blood clotting to maintain blood supply

• Histamine – increased permeability of blood vessels

• Serotonin – cause vasoconstriction and increased permeability of blood vessels

• Prostaglandins – made from cell membranes. May stimulate fever, pain,

vasoconstriction and vasodilation, increased permeability

Inquiry Question Review: How does a plant or animal respond to infection? (7.2.4)


➢ Describe the plant responses to viral and fungal pathogens

➢ Describe the physical and chemical changes as a result of pathogens

Inquiry Question 3: How does the human immune system respond to

exposure to a pathogen?

Content Descriptor: Investigate and model the innate and adaptive immune systems in

the human body: (7.3.1)

1st line of defence:

Physical and chemical barriers which prevent the entry of pathogens to the body and make an

inhospitable environment for foreign pathogens. The first line of defence is passive.

Skin:

➢ Thick layer of keratin protein prevents penetration

➢ Dryness prevents growth

➢ Glands secrete anti-fungal chemicals

➢ Overcome through cuts, abrasions or burns

Mucous membranes:


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➢ Covering digestive and respiratory tracts

➢ Traps pathogens so they can be removed by cilia, coughing or sneezing

➢ Overcome through resistant spores

Cilia:

➢ Small hair like structures which occur in large numbers on the cell surface, used for

locomotion

➢ Beat like a series of oars, sweeping mucous

➢ Can be by-passed by avoiding them, infection of the upper respiratory tract

Other secretions and chemical barriers:

➢ Gastric juices destroy enzymes of pathogens

➢ Urine is acidic, inhibiting the growth of bacteria

➢ Resistant spores and antibiotics which disturb pH levels may weaken this barrier

2nd line of defence:

Once successful in penetrating the first line of defence, pathogens must now face the second line of

defence. This is non-specific and attempts to destroy any pathogens present before they can cause any

serious damage to the body. The mechanisms, or defence adaptations; cell death, inflammation,

phagocytosis and lymph activities.

1. Cell is injured by trauma or infection causing release of chemicals.

2. Histamine and other chemicals cause vasodilation and increased permeability of blood

vessels.

3. Increased blood flow and increased permeability causes inflammation.

4. White blood cells enter tissues, triggered by increased blood flow and chemical signals.

These include phagocytes such as macrophages which can engulf and digest foreign

material. Pus is a bi-product of the clean-up process, composed of dead tissue, pathogens

and white blood cells, as well as fluid from the capillaries.

a. Neutrophils – First to move to the infection site, working to fight short and acute

infections, self-destruct after a few days.

b. Macrophages – The largest phagocyte, long lasting. Fighting chronic infections.

After having engulfed an antigen, they release enzymes to destroy the particles

then display the antigen on the MHC II molecule on the surface of the cell, this

plays a vital role in the initiation of the third line of defence.

5. Cell death – Cells die to seal off a pathogen that is not being successfully defended by the

body (granulomas). A wall of dead cells is made, forming a capsule trapping the

pathogens inside. The debris is then destroyed by macrophages. These are common in

chronic diseases.

6. Lymph system – Lymph system involves the movement of lymph fluid around the body.

It is a one-way drainage system, that has no pump and relies upon locomotion of adjacent

muscles to operate. As well as housing B cells and T cells, they also house stationary

macrophages. When plasma from lymph is exchanged with the blood, pathogens get

caught up. These then get filtered through the lymph nodes, where they are destroyed by

macrophages.

7. Other secretions:

a. Interferons - Secreted by some cells when infected by viruses cause nearby cells

to produce anti-viral enzymes. Most effective in short term infections. Short

acting and non-specific.

b. Compliment system – A group of 20 proteins which stimulate phagocytes to

become more active or destroy membrane of invading pathogen.


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3rd line of defence:

Third line of defence is a specific response to a pathogen, aiming to neutralise pathogen and the

antigens through cell and antibody mediated immunity. Many of the interactions are dictated by

chemicals such as cytokines (interleukin)

Antigens:

➢ Anything which can stimulate an immune response

➢ MHC I molecules are found on almost all cells. These molecules are antigens but are

recognised as self-antigens

➢ MHC II molecules found on macrophages and B-cells

➢ Pathogens which enter the body are a source of non-self-antigens

➢ Failure to recognise self/non-self-antigens leads to auto-immune conditions

➢ Can range from microbes and their toxins to grain and pollen

Antibodies:

➢ Also called immunoglobulins are proteins made in response to antigens

➢ Through a variety of methods antibodies neutralise a specific antigen

Response:

1. Antigen is identified. This is either through being recognised by B-cells present in the

lymph nodes, or identified by macrophages, which present the antigen.

2. Helper T-cells recognise this identification, releasing interleukin 2 to stimulate their own

mass-reproduction. These helper T-cells then release chemicals which activate cytotoxic

T-cells and B cells.

3. The specific B-cell to the antigen identified is cloned rapidly and begin pumping out

antibodies to neutralise the antigen. Cytotoxic T-cells migrate to the area and begin

attacking and killing infected cells.

4. Memory cells of both B and T cells are created. When the antigen is identified to the

second time, these memory cells are far faster to respond, reacting so fast that sometimes

symptoms do not even present. The advantage of these over regular cells is that memory

T-cells do not require helper T-cells to stimulate them, and memory B-cells produce

antibodies extremely quickly.

5. Once the infection has been defeated, suppressor T-cells halt the immune response

B-cells:

➢ Mature in bone marrow

➢ Released into the blood, lymph nodes, spleen and tonsils

➢ When activated, differentiate into plasma cells which secrete antibodies

➢ Also differentiate into memory B-cells

➢ Defend against extracellular pathogens

Cytotoxic T-cells:

➢ Mature in the thymus

➢ When activated migrate to the site of the infection and destroy infected cells

➢ Defend against intracellular pathogens

Content Descriptor: Explain how the immune system responds after primary exposure

to a pathogen, including innate and acquired immunity: (7.3.2)


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Terminology:

Acquired – Where the immunity is obtained from. This may be artificial (acquired through medical

intervention) or natural (acquired through natural methods).

Innate – Innate immunity refers to the non-specific immune response, the 1st and 2nd lines of defence.

Active vs passive – Whether the body had to produce the antibodies itself. If the antibodies had to be

produced by body cells, it is considered active. If the antibodies were injected, it is considered

passive.

Exposure:

➢ Primary exposure to an antigen is a very slow response, which can take up to a few weeks

➢ However, once the infection is fought, antibodies remain in the bloodstream for up to months

afterwards, meaning no symptoms are even displayed when the antigen is encountered for the

second time.


54

➢ Even if the level of antibodies falls beneath the minimum threshold, the later responses are

also much faster due to the extremely fast replication of memory B and T-cells and produce

much more antibodies. Later responses also require less antigen to initiate the response

Inquiry Question Review: How does the human immune system respond to exposure to

a pathogen? (7.3.3)


➢ Describe the innate and adaptive immune responses

➢ Describe the primary and secondary responses to pathogens

Inquiry Question 4: How can the spread of infectious disease be controlled?

Content Descriptor: Investigate and analyse the wide range of interrelated factors

involved in limiting local, regional and global spread of a named infectious disease:

(7.4.1)

Local Control Methods:

➢ Engaging with local communities through education awareness campaign about the

symptoms and associated risks

➢ Having anti-bacterial gel at the entry and exit to buildings

➢ Reporting and isolation of individuals, such as the separation of confirmed cases from

suspected cases in treatment centres

➢ Vaccines are given to those who have been in contact with the infected

➢ Lowers risk of transferal from person to person, however is likely to breakdown if there is a

lack of trust between local authorities and locals

Regional Control Methods:

➢ Tracing anyone who was or has been in contact with the infected to ensure the disease is not

spread to other areas

➢ Fast targeted teams deployed to isolate the sick

➢ Media notifications played a vital role in raising the alarm

➢ Isolation of villages via roads, to contain the sick and protect the healthy


55

➢ Can be a large drain on resources, technology may not be readily available to the developing

world.

International Control Methods:

➢ Stockpiling of vaccines in the case of an international outbreak

➢ International monetary and medical support

➢ WHO may recommend restriction to international trade (pursuant to the IHR 2005)

➢ Quarantining those from west African nations if fever like symptoms are displayed

➢ Resources of international community are usually far better suited to tackle large issues

➢ Can bring a wide range of doctors with better training

➢ Intervention by the international community can lead to cultural misunderstandings which can

brew hostility

Content Descriptor: Investigate procedures that can be employed to prevent the spread

of disease, including but not limited to:

Hygiene practices: (7.4.2)

➢ Hand washing and showering – prevent the build-up of pathogens on the skin which may

breach the first line of defence through abrasions.

➢ Safe disposal of waste – prevents diseases spread indirectly through faecal matter such as

cholera

➢ Covering mouth and nose when sneezing/face masks – prevents the spread of diseases

directly by denying a method to move from one host to another

➢ Safe cooking practices – Effective cooking eliminates harmful pathogens such as tapeworms

and bacteria in food, can also denature prions.

➢ Useful in preventing the local spread of disease

Quarantine: (7.4.3)

➢ A state, period, or place of isolation in which people or animals that have arrived from

elsewhere or been exposed to infectious or contagious disease are placed.

➢ Can be a large strain on resources and can make it difficult to provide care to quarantined

individuals.

➢ Useful in preventing international and regional spread of disease

Vaccination, including active and passive immunity: (7.4.4)

Vaccination:

➢ The process of exposing an individual to a weakened or inactive version of a pathogen, which

initiates and immune response.

➢ A form of artificially acquired active immunity.

➢ Injection of antibodies:

➢ A form of passive immunity can be obtained through the transfusion of antibodies from one

person to another.

➢ This is restricted however, as the levels of antibodies in the donor needs to be high enough to

fight off infection and also must be an appropriate blood type.

Vaccine types:

➢ Whole agent – Contains whole micro-organisms:

• Inactivated (killed by chemical treatment). No risk of contraction

• Attenuated (weakened by mutation). Low risk of contractions


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➢ Subunit vaccine – Contains some part or product of the micro-organism to produce an

immune response.

• Recombinant vaccine – Genetic engineering techniques used to cause other microbes

such as yeast to produce the desired antigen.

• Toxoid – Bacterial toxins that have been inactivated

• Conjugated – Polysaccharide capsules are combined with proteins such as toxoids

from other pathogens

• Acellular – Fragmentation of a conventional whole-agent vaccine and collecting the

desired fragments of antigens.

Polio:

➢ Virus which attacks nerve cells and central nervous system

➢ Jonas Salk created a vaccine which was injected and had a 60-70% prevention rate. However,

after 200 people contacted the disease from the vaccine, causing 11 deaths, testing was halted.

➢ Albert Sabin produced an ingestible vaccine through studying a rare form of the polio virus in

chimpanzees.

Public health campaigns: (7.4.5)

➢ Notifiable diseases must be reported to authorities to track and control their movement via

other mechanisms

➢ Quit smoking campaign and slip, slop, slap aim to raise public awareness about the dangers

and support groups which can help.

Use of Pesticides: (7.4.6)

➢ Chemicals that destroy organisms considered to be pests.

➢ An example of this is DDT pesticide which is used to destroy body lice to control typhoid

➢ Use of pesticides can be used to control insect vectors, but can lead to resistance of organisms

to pesticides limiting their effectiveness

Genetic engineering: (7.4.7)

➢ Alteration of genome by adding or removing genes

➢ Producing disease resistant strains of plants and animals:

• Cotton resistant to pests

• Investigation into changing the DNA of banana trees to make protect them from the

insect vector of the BBTV virus.

Content Descriptor: Investigate and assess the effectiveness of pharmaceuticals as

treatment strategies for the control of infectious disease for example:

Antivirals: (7.4.8)

➢ Drugs which can treat people already infected with a virus

➢ Prevent of limit infection when given before or after exposure

➢ Only effective for the duration of the time frame in which they are used

➢ Act by arresting the replication of viral cycles at different stages

Antibiotics: (7.4.9)

Method of antibiotics:

➢ Prevent the cell wall from forming when bacteria divide, for example penicillin

➢ Destroy the cell membrane for example miconazole

➢ Interfere with protein synthesis such as erythromycin


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➢ Inhibit enzymes such as sulphanilamide

➢ Do not work on viruses nor prions

Spectrum:

➢ When antibiotics are prescribed, they are usually done so with reference to the type of

bacteria.

➢ If the bacterial species is unknown, broad spectrum antibiotics will be used

➢ If the species is known, the bacteria will be specific to the type of bacteria, usually linked to

the gram stain.

Resistance:

➢ Excessive use of antibiotics has led to many bacteria becoming resistant, which has

significant impacts for hospitals.

➢ This can occur through natural selection, but also may be a product of unfinished courses of

antibiotics.

➢ Bacteria can achieve resistance through the swapping of plasmids, or through transduction

with viruses.

Content Descriptor: Investigate and evaluate environmental management and

quarantine methods used to control an epidemic or pandemic: (7.4.10)

Malaria:

Malaria is a disease caused by the Plasmodium protozoan and spread by mosquitos. Symptoms

include fever, tiredness, vomiting, headaches and death.

Environmental management – Intervention and targeting of one of the breeding areas or mosquitos.

The breeding areas such as ponds or water basins can be drained through irrigation and water

management. These areas can also be managed through treatment with oils, toxins or larvicides. These

have been shown to be effective in decreasing the mosquito population and thus reducing the

effectiveness of the malaria vector.

Alternative intervention methods such as introducing fish to eat the mosquito larvae have had limited

effectiveness.

Quarantine – Quarantine for malaria patients is not required nor effective in controlling the malaria

pandemic since it is spread via the insect vector.

Content Descriptor: Interpret data relating to the incidence and prevalence of infectious

disease in populations, for example:

Mobility of individuals and the portion that are immune or immunised: (7.4.11)

Polio


58


59

Malaria or Dengue Fever in South East Asia: (7.4.12)

Malaria

Primary countries affected in South East Asia:

➢ Bangladesh

➢ Bhutan

➢ India

➢ Indonesia

➢ Maldives

➢ Myanmar

➢ Nepal

➢ Sri Lanka

➢ Thailand

Movement into cities and urbanisation has increased the access to medicine, which has tended to

increase the incidence of drug resistant malaria, in some regions resistants rates of parasites reaches

80%.

Populations at greatest risk are rubber tappers in Thailand, with an incidence of 46.29%, with other

high-risk groups including infants and pregnant women. Overall incidence is 2.5-2.8 million cases.

Worldwide, malaria kills approximately 435,000 people every year, with a majority under the age of

five.

Content Descriptor: Evaluate historical, culturally diverse and current strategies to

predict and control the spread of disease: (7.4.13)

Malaria:

Strategy Description of the strategy Evaluation of its effectiveness in relation

to modern methods

Plague doctor

outfits

Prevent miasma, or bad air from

having access to the body. This was

thought to prevent the spread of the

disease, as well as herbs near the

mouth and nose supposedly filtered

air.

Prevention of contact is not extremely

effective when considering the plague

was spread by an insect vector, as the

outfits would not protect from lice. It

would have been more effective to kill

the insect vector.

However, the use of protective equipment

would have value for a pathogen which is

transmitted by direct contact.

Pomander A ball or container of an aromatic

substance placed supposedly

protected against infection.

Holds no modern effectiveness

Bleeding with

leeches

Used for chronic pain and a variety of

ailments. Purified the blood and

removed the bad blood from the

system. Solving an imbalance of the

four humors.

Use of leeches has significant value for

surgery because they inject anti-

coagulant. Can be used to attach removed

members. However, the use to treat an

imbalance of humors has no medical

value.


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Bleeding by

the barberry

surgeon

Bleeding and blood-letting was often

performed by barbers to balance out

the humors

Holds no modern effectiveness

Traditional

Chinese

Medicine

Over three thousand years ago,

Chinese medicine advocated for

cleanliness in food, water as well as

personal hygiene. Also made

connections between undercooked

pork and tapeworm.

Chinese also used the Wing-hao

remedy to treat malaria. The active

ingredient, artemisinin is used to treat

malaria.

There are also many homeopathic

remedies which have little or no

value

Use of general hygiene is significant in

controlling the spread of disease.

Lemons and

limes on ships

Used to cure scurvy by providing

sailors with vital vitamin C

Very effective for the treatment of scurvy

Modern methods to control disease include the aforementioned (7.4.2-7.4.7). Modern strategies also

include computer simulations of the spread of disease such as Ebola and HIV to predict and evaluate

the most effective methods to target control.

Content Descriptor: Investigate the contemporary applications of Aboriginal protocols

in the development of particular medicines and biological materials in Australia and

how recognition and protection of Indigenous cultural and intellectual property is

important, for example:

Bush medicine: (7.4.14)

Definition:

Practices and belief systems used in the maintenance of good health

Tea tree oil and Emu bush:

➢ Used by indigenous people as an antiseptic

➢ Used by pharmaceutical companies to make widespread antiseptic

Eucalyptus oil:

➢ Used by indigenous people as an antiseptic

➢ Used by pharmaceutical companies to make mouthwash and throat lozenges

Smoke bush in Western Australia: (7.4.15)

Use:

➢ Used for thousands of years for natural healing properties, inhaled to help cure colds and a

variety of ailments

Controversy:

➢ Investigated in 1980’s for use in treatment of HIV

➢ WA government signed patent granting rights of the product to the USA without

acknowledging or compensating indigenous people, in which the government was paid 1.5

million, while royalties may exceed 100 million / year.

Recognition:

Recognition of Indigenous people is significant for two primary reasons. First, it is vital to recognise

the validity of Indigenous cultural practices and the consequent contribution of such to the


61

establishment of modern medicine. Secondly, financial compensation is necessary to ensure the

solidification of the former recognition but also to prevent the exploitation of indigenous culture by

large corporations.

Inquiry Question Review: How can the spread of infectious disease be controlled?

(7.4.16)


➢ Understand the control methods for a variety of infectious disease

➢ Compare these techniques in effectiveness to past control methods

➢ Describe the use of antivirals and antibiotics

➢ Describe the Indigenous uses of medicine and why recognition of such is significant


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Module 8: Non-infectious Disease and Disorders

Inquiry Question 1: How is an organism’s internal environment

maintained in response to a changing external environment?

Content Descriptor: Construct and interpret negative feedback loops to show

homeostasis by using a range of sources, including but not limited to:

Temperature: (8.1.1)

Feedback loops:

Temperature:


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Glucose: (8.1.2)

Content Descriptor: Investigate the various mechanisms used by organisms to maintain

their internal environment within tolerance limits, including:

Trends and patterns in behavioural, structural and physiological adaptations in

endotherms that assist in maintaining homeostasis: (8.1.3)

Heat Exchange:

Organisms must protect their core body temperature, as the lowering of core temperature reduces the

speed of metabolism and bodily functions causing cell and eventually organism death. Endotherms

have better physiological adaptations for thermogenesis and thus do not need to gain heat energy from

the sun. Ectotherms rely mostly upon behavioural and structural adaptations to maintain temperature

homeostasis.

Structural:

Counter current heat exchange - Veins and arteries to and from extremities are adjacent, allowing

warm blood heading to the extremities to warm the cool blood returning.

Body size – Smaller organisms have a higher surface area to volume ratio. This makes it harder to

smaller animals to retain heat.


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Feathers, blubber and fat – Insulation

Physiological:

Vasodilation and vasoconstriction – Muscle contracts to move blood vessels closer to or away from

the surface of the skin.

Sweating – Sweat released evaporated removing heat from the skin.

Behavioural:

Seeking shade and basking – Movement to different locations takes advantage of the natural heat

differences.

Huddling – Reduces surface area and thus reduces size which heat can be lost across.

Plant temperature control:

➢ Temperature affects germination times

➢ Underground bulbs which stay dormant until temperatures decrease

➢ Vernalisation –Tthe delaying of flowering until they have been exposed to a certain level of

coldness.

➢ Small waxy leaves

Internal coordination systems that allow homeostasis to be maintained, including

hormones and neural pathways: (8.1.4)

The nervous system:

➢ Involved in the coordination of messages throughout the body

➢ Can be broken down into:

• CNS – Brain and spinal cord

• Peripheral nervous system – Consists of all nerves outside the brain and the spinal

cord

➢ Stimulus response model:

1. Receptor – A part of the body which can receive stimuli

2. Sensory neurone – Carries message from the receptor to the CNS

3. Connector neurones – Located in brain and spinal cord, assist in delivering message

4. CNS – Receives the message and processes

5. Motor neurone – Carry messages from the brain to muscles and effector organs

6. Effector organs – Carries out the desired response

Compare nervous and endocrine systems:


65

Aspect Endocrine Nervous system

Transmission Chemicals through the

bloodstream

Electrochemical impulses

through neurons and synapses

Speed of transmission Hormones take longer time to

act, as the organs or

neurosecretory gland take

time to be released and travel

through the bloodstream

Very quickly, with response

occurring almost immediately

after stimulus is detected

Cells contacted Every cell which is connected

to the circulatory system

Only cause a response in the

muscles which are a part of

the pathway. This means it

may also be limited to those

which are connected to these

pathways

Time for effect Many minutes or hours as the

hormones interact with target

cells to produce a response

Very quickly, milliseconds

Duration of effect Usually long lasting Short lasting

Receptors:

➢ May detect internal or external

➢ Proprioceptors – Muscle and movement

➢ Mechanoreceptors – Responding to touch pressure and pain

➢ Chemoreceptors – Activated by binding to chemicals, mouth and nose

➢ Photoreceptors – In the retina

Hormones:

➢ Simple endocrine pathway – Stimulus leads to secretion of hormone which reacts with target

cells

➢ Simple neuroendocrine pathway – Stimulus is detected by a sensory neuron stimulating a

neurosecretory cell to release a neurohormone

➢ Examples include glucagon and oxytocin. ADH is also secreted by hypothalamus causing

increased water absorption into the blood by kidneys

Mechanisms in plants that allow water balance to be maintained: (8.1.5)

Xerophytes are plants adapted to arid regions

➢ Generally, have leaves with thick waxy cuticles

➢ Smaller leaves

➢ Large root systems

➢ Tightly packed epidermis layer

➢ Stomates are small pores in the leaves of plants, these are closed to reduce water loss

➢ Leaves sometimes roll to cover stomates and prevent water loss

Hydrophyte needs large amounts of water


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➢ Single layer for upper and lower dermis for air pockets

Mesophyte needs moderate amounts of water

Mangroves:

➢ Osmoconformers allow the osmorality of their intestinal fluid to follow that of the

environment

➢ Osmoregulators use active transport to maintain constant osmorality

➢ Mangroves use pneumatophores to absorb oxygen for roots

➢ Accumulate salt on leaves and old branches to be jettisoned.

Inquiry Question Review: How is an organism’s internal environment maintained in

response to a changing external environment? (8.1.6)


➢ Draw and interpret feedback loops

➢ Describe the variety of mechanisms in organism that enable homeostasis

Inquiry Question 2: Do non-infectious diseases cause more deaths than

infectious disease?

Content Descriptor: Investigate the causes and effects of non-infectious diseases in

humans, including but not limited to:

Genetic diseases: (8.2.1)

Caused by genetic abnormalities

➢ Point mutations

➢ Chromosomal mutations

Down syndrome:

➢ Three copies of chromosome 21 (trisomy 21)

➢ Wide eyes

➢ Short flat nose

➢ Heart defects

➢ Intellectual learning difficulties

➢ Assistance to those with down syndrome includes early intervention to help children develop

skills that help them in the community

Diseases caused by environmental exposure: (8.2.2)

Caused by genetic abnormalities

➢ Exposure to toxic substances

➢ Radiation

➢ Drug abuse

Melanoma:

➢ Exposure to UV radiation (physical mutagen which breaks DNA backbone)

➢ Pigment producing cells become cancerous when the tumour suppressor genes and cell death

regulatory genes become damaged

➢ Removed through surgery


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➢ Significant harm prevented through sun-safety and early detection

Nutritional diseases: (8.2.3)

Caused by incorrect nutritional intake, an imbalance in diets

Scurvy:

➢ Lack in vitamin C

➢ Loss of appetite depression and weakness

➢ Brittle bones

➢ Prevented through consumption of fruit and vegetables

Cancer: (8.2.4)

Cancer:

Normal cells are programmed to die in a process called apoptosis, usually corresponding with the time

that they have accumulated damage which prevents them from carrying out their normal function.

Cancer cells have mutated such that their regulatory genes have been switched off, allowing them to

continue to replicate regardless of the damage they have accumulated.

Bowel cancer:

➢ Inner lining rectum

➢ Causes a hard-fibrous mass

➢ Threat of metastasising and moving to the liver or lungs, where it can vastly affect vital cell

function

Content Descriptor: Collect and represent data to show the incidence, prevalence and

mortality rates of non-infectious diseases for example:


Scurvy:

Scurvy is a nutritional disease caused by vitamin C deficiency. It was first reported in 1550 BC, where

the diagnosed symptoms were treated with onions and vegetables. Classical symptoms include brittle

bones, bleeding gums and losing teeth, discoloured skin.

Primary risk factors include alcohol intake, tobacco use, haemodialysis and poor nutrition. Prevalence

varies, from 7.1% in the USA to 73.9% in northern India.

In early human history the mortality rates were extremely high, around 50%. As seen in the diagrams

below, the mortality rates for scurvy at the beginning of the 20th century began very high, at around

10%. However, soon following the publishing of the structure and synthetic production of vitamin C

in 1927, as well as increased awareness and understanding of treatment, the mortality rate plummeted.

Dying of scurvy is a very rare occurrence in developed nations.


68

Diseases caused by environmental exposure: (8.2.6)

Melanoma:

Melanoma, skin cancer has a number of associated risk factors. The leading cause is from exposure to

UV radiation, which can cause the breaking of the DNA backbone or the formation of a thymine

dimer. This may cause errors in cell regulatory genes, causing the uncontrolled growth cell growth

and replication of cancers.

Characteristic symptoms can be a change in colouration or size of an existing mole, or abnormal

change in skin colour.

Incidence of melanoma was 12,036 in Australia in 2012, with a mortality of 1,520. This number has

increased to 15,229 in 2019. During the 1980’s, the incidence rose at a rate of 5% per year, and since

1990 it is increasing at 2.8% per year. This is likely reflective of increased awareness and prevention

methods as a result of education campaigns. Currently, there is a 91% chance of surviving at least 5

years with melanoma.

Scurvy mortality rates England

Scurvy incidence England


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1/14 Australian men and 1/24 women will be diagnosed with melanoma in their lifetime, with current

prevalence at 55,128.

Inquiry Question Review: Do non-infectious diseases cause more deaths than

infectious? (8.1.7)


➢ Describe the various causes of non-infectious diseases

➢ State statistics relating to incidence, prevalence and mortality of these diseases

Sample Question:

Do non-infectious diseases cause more deaths than infectious?

Non-infectious disease is responsible for more deaths in developed nations, while infectious is

responsible in developing nations. This can be attributed to a number of different factors:

Developing Developed

Health care Low quality due to being overburdened by

large populations with low health

expenditure. Furthermore, fewer people

have any access to health care to due

associated costs which cannot be paid for.

High quality of health care and

high access, although this is not

the case in countries such as the

USA

Hygiene

and

vaccination

Usually low levels of hygiene and

vaccination that enables infectious disease

to spread easily.

Usually high levels of hygiene

and vaccination which prevents

spread of infectious disease.

While this is extremely useful

against infectious disease, it

cannot prevent non-infectious

Melanoma incidence rates Australia


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Pollution Usually low levels of air pollution due to

smaller industry

Higher education and public education.

High levels of pollution which

leads to infectious diseases such

as lung disease

Diet Usually off raw resources such as farming

and fishing in low quantities. This means

lower levels of obesity but higher chance

of death due to contamination such as that

of water-ways. Lack of nutrition such as

vitamin A.

High calorie intake diets which

leads to obesity, risk factors in

heart disease. Clean food reduces

risk of infectious disease.

Inquiry Question 3: Why are epidemiological studies used?

Content Descriptor: Analyse patterns of non-infectious diseases in populations,

including their incidence and prevalence, including not limited to:


Prevalence of diabetes within the USA:

Analysis of Prevalence

Diabetes a partially nutritional disease which results in the body being unable to correctly regulate

blood sugar levels (8.1.2).

While most of the west and central united states is sporadic and random in the prevalence, there is a

definite trend of increase prevalence in the south east, namely the states of Mississippi and Alabama,

which have almost entirely the highest rate of >11.66%. Generally, diabetes is inversely related to

income and education, with major risk factors including heart disease, poor diet and high sugar and fat

intake. In general, these states tend to have lower levels of education (49th and 45th out of 56

territories). These lower education levels can also be correlated with lower income which can

contribute to the poor diet risk factor. Although somewhat anecdotal, there is a cultural trend of

southern states to regularly eat fried and deep-fried foods, which tend to be high in fats. This may


71

explain the poor diet of some of these states but does not account for the differences between states

which have similar diets (Louisiana vs Mississippi).

Disease caused by environmental exposure: (8.3.2)

Incidence of melanoma worldwide:

Analysis of Incidence:

Melanoma is a skin cancer which is mostly attributed to exposure to UV radiation. When considering

the rotation of the Earth and the corresponding seasonal oscillations, the areas around the equator tend

to receive far more sunlight and thus UV radiation than those further towards to poles. Thus, it would

be expected that those towards the equator would have higher incidence of Melanoma. However, this

is not reflected in the data, with the highest incidence occurring in nations far away from the equator

(USA, Canada, New Zealand, Australia, Norway), all of which have the highest incidence

(4.1+/100,000), compared to nations along or next to the equator (Somalia, Ethiopia) which have

extremely low incidence (<0.89/100,000). This may be accounted for by the physical adaptations of

many of the inhabitants of these regions, which tend to have high amount of melanin in the skin which

helps protect against UV radiation. For example, Nigeria, which has an incidence of 0.48-

0.89/100,000 has less than 1% of the population Caucasian. This biological advantage for those in

these areas outweighs the increased exposure to the sun.

Content Descriptor: Investigate the treatment/management, and possible future

directions for further research, of a non-infectious disease using an example from one of

the non-infectious disease categories listed above: (8.3.3)

Cystic fibrosis treatment: (6.2.2)

Cystic fibrosis (CF) is caused by a frameshift mutation, causing cells to not produce an enzyme which

mediates the conditions in normal humans. Thus, it is a genetic condition.

A large area of research is currently dedicated to using biotechnology to reverse the mutation of the

CFTR gene. To achieve this reversal, correct pieces of DNA need to be delivered to individual cells.

From there, either the cell incorporated the correct version of the CFTR gene (integrating gene

therapy), or it temporarily uses an attached copy (non- integrating gene therapy). While trials in mice

have been promising, the appropriate method of delivery of the genes still requires further research.


72

One method currently under investigation is through attachment to a hybrid virus, which delivers the

DNA.

The benefit of genetic treatments for CF is that it will likely be effective for any mutation of the

CFTR gene and therefore useable by all CF patients.

Other areas of research include non-genetic treatments, such as the development of anti-inflammatory

micro-molecules which block multiple of the enzymes involved in inflammation.

Content Descriptor: Evaluate the method used in an example of an epidemiological

study: (8.3.4)

Epidemiological studies:

For the scope of the HSC, epidemiological studies can be divided into two primary areas:

a) Case control – Composed of two groups, one with the condition (case) and one without

condition (control). A large amount of data is collected about these two groups, and trends are

searched for which the case group have in common which the control group does not.

b) Cohort – Two groups of people are assembled, those who have a set exposure to a potential

risk factor and those who do have the exposure. These two groups are closely monitored over

a large amount of time to track the development of the disease. If there is a strong correlation

between the case group and the development of the disease, there may be a link between the

exposure and the condition.

Qualities of a good epidemiological study:

1. Large sample group

2. Identification of confounding factors (external unaccounted for variables)

3. Diverse sample group (ages, ethnicity, sex)

4. Accounts for participation bias (for example those who have had food poisoning may

perceive the food they ate differently after being diagnosed. There may also be social pressure

to respond in a certain way to questions, for example regarding smoking, alcohol or sexual

habits.

5. Uses medical examination where possible rather than simply a survey. This may include

blood tests or microbial analysis.

6. Ensuring that the participation group is reflective of the demography of the entire population

7. Clearly stating exclusion factors and exclusion qualifications

8. Large quantities of data

9. Follow up investigation or medical check-ups

10. Peer reviewed

For more information on the preparation of epidemiological studies, see:

https://pmj.bmj.com/content/postgradmedj/80/941/140.full.pdf

Content Descriptor: Evaluate, using examples, the benefits of engaging in an

epidemiological study: (8.3.5)

Benefits:

The primary benefit which arises from epidemiological studies is to discover or provide substantial

evidence for significant risk factors associated with a non-infectious disease. The most famous

example of this was from the studies performed lining smoking cigarettes to lung cancer. Through a

length number of studies, there was significant evidence that linked smoking to lung cancer. This

pressured governments, such as the Australian government to implement laws to disincentivise

https://pmj.bmj.com/content/postgradmedj/80/941/140.full.pdf


73

smoking and protect the population from harm. Thus, engagement in an epidemiological study helped

understanding of disease which has caused reduction in death as a result.

Knowledge of the causative agents of disease aids in targeting methods to prevent, control and treat

non-infectious diseases.

Inquiry Question Review: Why are epidemiological studies used? (8.3.6)


➢ Analyse the patterns and provide reasons for the distribution of non-infectious disease

➢ Describe an area of further research for a non-infectious disease

➢ Describe the components of a good epidemiological study and use this knowledge to evaluate

methods of an epidemiological study

Inquiry Question 4: How can non-infectious disease be prevented?

Content Descriptor: Use secondary sources to evaluate the effectiveness of current

disease-prevention methods and develop strategies for the prevention of a non-

infectious disease, including but not limited to:

Educational programs and campaigns: (8.4.1)

Slip! Slop! Slap!:

Key findings:

➢ Melanoma cases among young people has fallen 5% a year since the 1990s.

➢ There has also been a drop in some skin cancers in those aged up to 45.

Slip-slop-slap is an education campaign targeted at reducing cases of melanoma amongst Australians.

Since the beginning of the education campaign in 1981, the campaign has seen significant success

with melanoma cases has falling from 25 per 100,000 in 1996 to 14 per 100,000 in 2010 among

people aged 20 to 24. This decrease can most likely be attributed to the increased awareness as a

result of the campaign, allowing for the simple steps to mitigate the risk of UV exposure.

It is further estimated that the campaign will have prevented more than 43,000 skin cancers and 1,400

skin cancer deaths in Victoria between 1988 and 2011. Studies also showed SunSmart has saved

money as well as lives, returning $2.20 to the public for every dollar invested in the program, in terms

of reduction of treatment cost.

Genetic engineering: (8.4.2)

Treatment of diabetes using genetic engineering:

Through recombinant DNA methods, humans have been able to artificially produce insulin using

bacteria. This synthetic insulin, known as Humulin has been licensed for human use since 1982. This

Humulin is identical to the insulin produced in the pancreas of humans, and thus has been effective in

treating diabetes patients.

Inquiry Question Review: How can non-infectious disease be prevented? (8.4.3)


➢ Describe different ways to treat non infectious diseases


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Inquiry Question 5: How can technologies be used to assist people who

experience disorders?

Content Descriptor: Explain a range of causes of disorders by investigating the

structures and functions of the relevant organs, for example:

Hearing loss: (8.5.1)

Structure and function of ear:

Outer ear:

➢ Pinna collects sound from the environment

➢ Auditory canal channels waves into the ear

➢ Ear drum vibrates, transmitting sound waves to middle ear

Middle ear:

➢ Ossicles together serve to amplify the sound waves

➢ Eustachian tube connects middle ear to nose and throat allowing mucous to drain

Inner ear:

➢ Oval window has vibrations transferred from the middle ear

➢ Cochlea and organ of Corti transform vibrations in hair cells to electrical signals

➢ Semicircular canals detect balance rather than sound

➢ Auditory nerve transmits information to brain

Ailments of the ear:

Caused by damage or blocking of the structure of the ear

Glue ear:

➢ Build-up of mucous in middle ear preventing ear drum vibrating

Swimmers ear:

➢ Exposure to heat and moisture

➢ Swelling of skin layer in auditor canal


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➢ Prevents sound from being transmitted

Meniere’s disease:

➢ Excessive build-up of fluid in inner ear

➢ Bursts causing vertigo and hearing loss

Visual disorders: (8.5.2)

Structure and function of the eye:

External eye:

➢ Conjunctiva – Mucous membrane that keeps the eye moist

➢ Cornea – Keeps shape of the eye and begins refracting light

➢ Iris – Coloured muscle which contracts to changes the amount of light let into the eye

Refractive elements:

➢ Lens – Flexible transparent bulb which can be pulled to change the amount of refraction

➢ Ciliary body – Contracts to change shape of lens

➢ Aqueous humour – Between lens and cornea

➢ Vitreous humour – In eyeball cavity

Receiving layers

➢ Sclera is outer coat of eyeball. Protects and maintains shape

➢ Choroid – Between retina and sclera, nourishes the layers

➢ Retina – Photoreceptive layer with rods and cones

Ailments of the eye:

Damage to the structure or blocking light from entering the eye.

Myopia:

➢ Short sightedness, image falls in front of retina

➢ Lens is too thick or cannot flatten enough

Hyperopia:

➢ Far sightedness, image falls behind the retina


76

➢ Lens is too thin and cannot refract light enough

Cataracts:

➢ Painless sight defects causing a blurring of vision on the lens

Loss of kidney function: (8.5.3)

Structure and function of the kidney:

Excretion:

➢ Some fluid gets squeezed out under high pressure in the glomerulus (prevent protein and large

molecules)

➢ Protein cannot move through

➢ Waste is removed and not re-absorbed

Osmoregulation, salt balance, blood pressure:

➢ Loop of Henley arranged down towards the medulla

➢ Removes excess salts which in turn lowers blood pressure

➢ Reabsorb crucial water

Aids homeostasis through:

➢ Selective reabsorption

➢ Secretion of foreign material not required

Ailments of the kidney:

➢ Kidney stones

➢ Diabetes – Kidney damage and damage to glomerulus

➢ Infection of inflammation of glomerulus

Content Descriptor: Investigate technologies that are used to assist with the effects of a

disorder, including but not limited to:

Hearing loss: cochlear implants, bone conduction implants, hearing aids: (8.5.4)

Cochlear Implant:

➢ Involves an external sound processor and an implant in place of damaged cochlear cells


77

➢ Vast hearing improvement

➢ Risks associated with the implant surgery

➢ Expensive and requires maintenance

Bone conduction Implant:

➢ Alternative to hearing aids

➢ Internal and external component

➢ Similar to hearing aid except it bypasses the middle ear and conducts sound through bone

➢ Good for single ear hearing loss

➢ More expensive than hearing aids and involve surgery

Hearing aid:

➢ Amplifies the sound

➢ Cheap but not extremely effective

Visual disorders: spectacles, laser surgery: (8.5.5)

Spectacles:

➢ Cheap curved lenses which change the focal distance, causing sharper images

➢ Concave for myopia and convex for hyperopia

➢ Can be broken and some people do not like glasses

Laser surgery:

➢ Uses lasers to shape the cornea to change focus

➢ Expensive but can prevent the need for glasses

Loss of kidney function: dialysis: (8.5.6)

Haemodialysis:

➢ Performed in a home or centre and done three times a week

➢ Needles used to access the blood and it is taken through a specialised filter which cleans the

blood (dialyser)

➢ Traveling to hospitals may be expensive and time consuming and the procedure performed at

home has risk of infection

Peritoneal:

➢ Popular method since it does not involve journeying to the hospital

➢ Catheter is placed in the stomach

➢ Can be done during the day or overnight

➢ Fluid fills the cavity and is then used to clean the blood

Transplant:

➢ Receive a living or deceased donor

➢ Have an operation to receive the kidney

➢ More suited to younger patients

➢ May be expensive for both involved since care time is lengthy

Content Descriptor: Evaluate the effectiveness of a technology that is used to manage

and assist with the effects of a disorder: (8.5.7)

Evaluate the effectiveness of spectacles for treatment of hyperopia and myopia:


78

The purpose of the eye is to collect and redirect light into the retina, where it can be changed into

chemical signals and sent to the brain. The lens is a crucial part of this process, its flexible body able

to contract or release via pull from the adjacent ciliary body. This accommodation allows for light of

different distances to be focused sharply on the retina for clear vision.

In age, these ciliary muscles may become weak, or the lens may become misshapen, leading to

myopia or hyperopia. If the lens is not stretched enough, if will refract light too much, causing the

focus of light to fall in front of the retina, known as myopia or short-sightedness. Conversely, if the

ciliary muscles weaken, the lens will not be able to stretch enough, causing the light to fall behind the

retina; hyperopia or short-sightedness.

Spectacles may be used to treat both of these conditions. Convex lenses can be used to increase

refraction and thus treat hyperopia, while concave lenses may be used for myopia. Spectacles are

easily available if they are non-prescription and if so, are also quite cheap. However, prescription

lenses may be very costly. While spectacles are effective in treating the conditions, they are only

effective while being worn, and may be inconvenient to carry on person at all times. An alternative to

this is laser eye surgery, which permanently alters the shape of the cornea to increase or decrease

refraction of light. This is permanent, meaning the benefit will stay with the treated individual,

however, mistakes may also adversely affect vision. Furthermore, these surgeries may be extremely

expensive.

Overall, spectacles are effective in treating myopia and hyperopia as they are effective and cheap.

However, for aesthetic or convenience purposes, it may be beneficial to consider alternatives such as

laser eye surgery.


1

Data Sheet

(5.1.6) – Hormonal control

Progesterone

produced by placenta

6-9 weeks

Successful

implantation

8-10 days after

ovulation

(5.4.4) – Sickle Cell Anaemia

Prevalence (USA) 100,000 (0.03%)

Prevalence (USA of

African Americans)

1/500 (0.2%)

Prevalence (USA of

Hispanic Americans)

1/1000 (0.1%)

(5.4.5) - SNPS

Minimum prevalence 1%

Occurs in 1/300 bases

Total SNPS variations 10 million

(5.5.3) - Huntingtins

Prevalence 5-7/100,000 (0.006%)

Non genetic incidence 10% of cases

Allele threshold ➢ <35 HD repeats

will not develop

➢ >40 HD repeats

will develop

➢ In between may

develop

(6.1.5) – Down Syndrome

Incidence % (USA –

women under 31)

0.125% of births,

Incidence value

(USA)

6000/year

(6.2) – Genetic engineering

AA (Aqu Advantage)

growth rate

2 X normal salmon

growth

Size of Alaskan

fishing industry

60,000 employed

Bt cotton cost

reduction in pesticide

use since 1997

93%

Bt decrease in water

consumption

3-4%

Worldwide demand

cotton

28 million tons

Bt cost effectiveness $180 more/hectare

Bt increase in land

efficiency since 1980

50% increase in

production/land area

GMO sunflowers

seed production

50% greater than

regular sunflowers

(7.4.12) - Malaria

Prevalence South-

East Asia

2.5-2.8 million

Highest incidence Rubber tappers in

Thailand – 46.49%

Worldwide mortality 435,000

Highest drug

resistance

80%

(8.2.5) - Scurvy

Prevalence (USA) 7.1%

Prevalence (Northern

India)

73.9%

Original mortality

rate

50%

(8.2.6) - Melanoma

Incidence (2012) 12,036/year

Mortality (2012) 1,520/year

Incidence (2019) 15,229/year

Incidence increase

(1980-1990)

5%

Incidence increase

(>1990)

2.8%

5 year survival rate 91%

(8.4.1) – Slip! Slop! Slap! (Melanoma)

Prevalence change in

young people

5% since 1990

Campaign began 1981

94%

3% 3%

Down Syndrome Causes

Non-disjunction of chromosomes

Translocation of Chromosome 21

Miotic errors


2

Prevalence 1996 (20-

24-year old’s)

25/100,000

Prevalence 2010 (20-

24-year old’s)

14/100,000

Prevention of skin

cancers (Victoria

1988-2011)

43,000

Prevention of skin

cancer deaths

(Victoria 1988-2011)

1,400

Public return in,

factoring reduction of

treatment cost

$2.20 : $1

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Biology HSC Notes by syllabus points · Examining frequency data: ... Content Descriptor: Investigate the use of technologies to determine inheritance patterns in a ... Trends and