Heredity

Dot Point 1Explain the mechanisms of reproduction that ensure the continuity of a species, by analysing sexual and asexual methods of reproduction in a variety of organisms.Asexual reproduction- involves only one parent and no sex cells or gametes, resulting in offspring that are genetically identical to the parent. Sexual reproduction- involves two parent, who produce offspring that contain a mix of the parent’s genes and therefore different to each other and their parents eg; pollination via insects, birds or wind (plants)

Sexual AsexualNo. of parents 2 1Genetic variation in offspring

High Low

Length of cycle Longer shorterExample Humans bacteria

Plants- Male- stamen = filament and anther Female – carpel = stigma, style and ovary

Animals; advantages and disadvantages off external and internal fertilisationInternal- fertilisation of the nuclei of a sperm and egg that occurs inside the bodyExternal- fertilisation of the nuclei of a sperm and egg that occurs outside of the body

Internal ExternalLikelihood of successful fertilisation of eggs

High Low

Location of development of zygote

Inside the female Outside female

Likelihood of fertilised egg surviving until birth

High low

Number of eggs produced Few Many Environment in which fertilisation occurs

Terrestrial Aquatic

Examples Dogs turtle

Plants; - Asexual - runner, bulbs, cuttings (plants- Sexual- pollination via insects, birds or wind (plants) can be self-pollination or cross

pollination. Fungi;

- Asexual- budding (where a part of the adult organism divides by mitosis and produces a small bud, which separates from the parent and grows into a new individual)

- Sexual- spores (produce huge number of spores, they are light so easily dispersed by wind, water or animals, they germinate in new locations to form a new fungus

Bacteria; - Asexual- binary fission (involves division of a eukaryotic cell into two- replicates DNA

and divides). Protists;

- Asexual- binary fission (involves division of a eukaryotic cell into two- replicates DNA and divides).

Dot Point 2Analyse the features of fertilisation, implantation and hormonal control of pregnancy and birth in mammals

Hormones- chemical substances that act as a messenger to the body, coordinating many aspects of functioning. Follicle stimulating hormone (FSH) causes an egg follicle to start developing in the ovary. Oestrogen- developing an egg produces oestrogen, peaks before ovulation Luteinising hormone (LH)- triggers ovulationProgesterone- an empty egg follicle produces progesterone to thicken the endometrium

Follicle- small sac found in the ovary that contains one immature egg, release oestrogen Ovary- female reproductive organ, contains follicles Corpus Luteum- develops after a follicle rupture and releases an egg during ovulation, releases oestrogen and progesterone. Menstruation- endometrium disintegrates, menstrual bleeding Endometrium- tissue that lines uterusFollicular Phase- first half of ovarian cycle, one follicle matures, oestrogen levels rise, stimulates thickening of endometrium, in middle egg burst out of follicle = menstruation Luteal Phase- second half of ovarian cycle, corpus luteum produces oestrogen and progesterone, causes endometrium to thicken and stabilise, at end corpus luteum disintegrates, decrease in progesterone and oestrogen resulting in ovulation.

Implantation- 1. Sexual intercourse2. Muscular contract causes semen to move into the vagina3. Sperm travels through cervix, into uterus and into an oviduct (fallopian tube)4. A single sperm fertilises an egg5. As a zygote travels down the fallopian tube to the uterus, it begins to grow through

mitosis and begins to develop into an embryo 6. Embryo implants in the endometrial wall of the uterus to continue developing

First Trimester- HCG rises rapidly, maintaining the corpus luteum, ensuring uterus remains receptive to an embryo. Decrease in GnHR, RSH, LH, preventing menstruation. Seconds Trimester – high levels of oestrogen and progesterone, corpus luteum deteriorates, placenta now produces these hormones Third Trimester - increases oestrogen, oxytocin triggers labours, causes muscular contraction, placenta releases prostaglandins stimulate contractions

Dot Point 3Evaluate the impact of scientific knowledge on the manipulation of plant and animal reproduction in agriculture

Agriculture is the growth of crops and animals for human needs Selective breeding- refers to the creation of organisms with certain desirable

characteristics. Natural Breeding, artificial insemination, artificial pollination and cloning Placing male and female people in a field together. AI- taking sperm from a male and inserting it into a female AP- taking pollen from one flower and inserting it directly into another flower using a

small brush. Cloning- A genetic identical copy of an organism using genetic engineering

techniques.

Positive ImpactsIncreased sale- more production or improved qualityIncreased resistance to certain pests and disease- save money and good for environment

Negative Impacts-Reduced biodiversity- undesirable traits bred out, more likely to suffer in change in environment

Scientific Knowledge about Reproduction

Reproductive Technique (and when it was introduced)

How reproduction is manipulated in plants and or animals using this techniques

Impact of Knowledge: Advantages and or disadvantages (or ethical concerns) of this technique.

Characteristics are likely to be passed onto offspring.

Selective Breeding- Is an ancient technique that has been used for tens of thousands of years.

Reproduction is planned and controlled for example a specific bull mates with a particular cow at a particular time.

This has allowed farmers to improve their breeding stock to make the product greater quality and a larger quantity. A disadvantage is is reduces the biodiversity and variety among a species but this is not seen as an ethical issue as it has been happening for so long.

Techniques that allow for the alteration of an organism’s genome and genes be transferred from one organism to another.

Cloning- is the production of new individuals that contain the same genetic information as the parent organism. This technology has been developed

Using this technique, the DNA can be transferred or specific genes can be transferred to improve the species. For example, GM has been used to improve the quality

The advantages of this is that you can clone something so it has exactly the same DNA and favourable characteristics. This eliminates error. However, for animals the disadvantages include significantly reducing the diversity and variety among a species which could lead to a dramatic suffering of the species if the environmental or other conditions change.

over the last few decades.

and yield of meat, milk, eggs and wool.

Dot Point 4Model the processes involved in cell replicationMitosisThe part of a cell cycle during which active nuclear division takes place, to ensure that replicated chromosomes separate and are equally distributed to the two identical daughter cells

- In somatic cells (body cells)- Responsible for growth and repair

G1 (first gap)- the cell grows and develops

S- synthesis of DNA to replicate chromosomes

G2 (second gap)- rapid cell growth and protein synthesis preparing for mitosis.

Prophase- DNA condenses, nucleus membrane disappears, spindles begin to form, chromosomes join in homologues pairs attached by centrosomes

Metaphase- chromosomes line up in the middle, spindles attach

Anaphase- chromosome separate putting chromatids apart, move to opposite sides of cell

Telophase- two new nuclei form, forms a cell plate where a cell wall will form

Cytokinesis – two new daughter cells are formed

MeiosisType of cell division that halves the chromosome number and gives rise to gametes that transmit genetic material from one generation to the next during sexual reproduction

- Happens in sex organs (ovaries and testes)- Creates 4 non-identical daughter cells- Creates egg and sperm gametes - 2 cell division- Haploid

Meiosis I Meiosis II- DNA replicates - Chromatin shortens and thickens to from

chromosomes - Chromosomes line up in homologous pairs

connected by centromeres (one maternal and one paternal)

- Crossing over occurs (swapping of genes)- Spindles attach, shorten and homologous

chromosomes break apart from centromere- Splits into 2

- Chromosomes line up individually - Spindles attach to centromeres- Spindles shorten, centromeres break and

chromatids move apart- Cytoplasm separates, cell and nuclear

membranes form chromosomes unci- 4 non-identical cells (gametes)

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

Nucleotide- phosphate, deoxyribose sugar, and nitrogenous base (Adenine and Thymine (2 bonds) or Guanine and Cytosine (3 bonds)).

- Parent DNA molecule unwinds and unzips (bonds break to from 2 strands) by an enzyme called helicase creating a fork

- Primase adds a short primer- DNA polymerase binds free nucleotides according the complementary base-paring

rule - Coil back into a double helix- 2 identical daughter DNA molecules - Is semiconservative eg; one leading and one lagging strand, one strand is the original

and the other is new.

Dot Point 5Access the effect of the cell replication processes on the continuity of species

- Ensures embryo survive- Allows for natural selection – survival of the fittest - Allows for mutation – changes in DNA- Fertilisation methods can occur to ensure individuals breed successfully

Dot Point 6Construct appropriate representations to model and compare the forms in which DNA exists in eukaryotes and prokaryotes

Prokaryotic EukaryoticExamples of organism Bacteria AnimalsNucleus & Membrane bound organelles?

No Yes

What shape are the chromosome(S)?

Circular Linear

Location of DNA Cytoplasm NucleusRelative amount of DNA Small LargeHow many chromosome are there?

One Multiple

In what additional place(S) can DNA be found?

The Plasmid Chloroplast and Mitochondria

Dot Point 7Model the process of polypeptide synthesis

- Transcription DNA is found in the nucleus and that is where the first process of polypeptide synthesis occurs. The first step is call transcription. Transcription is the process by which genetic information is copied from a section of DNA onto a messenger RNA molecule. The mRNA strand acts as a messenger which copies and carries genetic information from the DNA inside the nucleus to the ribosomes in the cytoplasm. During transcription a gene unwinds temporary at a particular strand which allows for an enzyme called RNA polymerase to move along the master DNA strand attaching free RNA nucleotides according to the complementary base-pairing rule. This is where the base Thymine is replaced with Uracil. Therefore, the mRNA bases are Adenine, Uracil, Cytosine and Guanine. Within this pre-mRNA there are coding regions known as exons which eventually get expressed as protein, are interrupted by noncoding regions (introns). During a process of RNA splicing, introns are removed and exons joined to form a mature mRNA molecule a coding sequence. The mRNA strand is then released, moves through the nuclear pore and into the cytoplasm to a ribosome.

- TranslationTranslation is the process by which the copied genetic information on the mRNA is converted into a polypeptide. Translation occurs when the mRNA in the cytoplasm attached to a ribosome. Once attached to the ribosome, tRNA becomes involved. The tRNA’s job is to transfer amino acids to the ribosome which are then made into polypeptides. tRNA consists of an RNA molecule which as 3 nitrogenous bases on one side and an amino acid on the other. The base sequence of the 3 nucleotides in the tRNA is called an anticodon. An amino acid contains both a carboxylic group and an amino group. Linking these two groups together is this carbon atom, which we call the alpha carbon. Then bound to the alpha carbon is a hydrogen atom as well as a unique side chain called the R group. The R group makes each of the 20 amino acids different characteristics, allowing it to react with other amino acids in specific ways Translation begins at the start codon AUG which is read on the mRNA. As the ribosome moves down the mRNA strand, peptide bonds form in-between the amino acids as the tRNA molecules line up according to the codons on the mRNA strand. For example, starting codon with pair up with the anticodon UAC. After the amino acid has bonded to another amino acid, the tRNA molecule is no longer needed and therefore is released. The polypeptide continues to grow until it reaches a stop codon either UAA, UAG or UGA. The polypeptide is the then released from the ribosomes. The polypeptide then links, folds with itself or other polypeptides creating a distinct 3D structure known as a protein.

- Accessing the importance of mRNA and tRNA in transcription and translation

MRNA- mRNA is a single stranded nucleic acid. mRNA consists of a ribose sugar, phosphate backbone and nitrogenous base (A, U, G, C). DNA does not leave the nucleus. As a result, a message must be sent from the nucleus to the ribosomes where protein synthesis occurs. This message is sent in to form the MRNA. Protein synthesis would therefore be impossible without MRNATRNA- tRNA is a small single-stranded nucleic acid. The tRNA molecule has a distinctive folded three loop structure one of the loops contains an anticodon; a sequence of three nucleotides, complementary to the corresponding sequence on the mRNA. Each Taya Renee has a corresponding amino acid attached to the opposite end to the anticodon. As a result of the complementary nature of the mRNA and tRNA codon-anticodon complex, the specific sequence of amino acids is required for protein synthesis to occur. protein synthesis for not be possible without tRNA.

- Analysing the function and importance of polypeptide synthesis If polypeptide didn’t exist there would be no proteins, thus no growth, repair, antibodies, storage, transport, chromosomes or enzymes. If polypeptide synthesis wasn’t working properly, protein could be deformed and dysfunctional. Eg; without polypeptide synthesis working to create functional enzymes metabolism would be too slow to maintain.

- Accessing how genes and environment affect phenotypic expression Phenotype- an organism’s physical expression of a particular characteristics. Determine by 2 things the genes that are present (genotype) and environmental factors.

Genotype- an organism’s genetic makeup for a particular characteristic

Genome- an organisms complete set of genetic material, different organisms have different genomes with different complexities

Alleles- alternative forms of the same gene eg; eye colour

Both genes and environment play a role, however, the amount is responsible for depends on the particular organism and the characteristics you’re looking at. For some characteristics, genes are the bigger determinant eg; eye colour while for other characteristics, the environment is bigger eg; weight.

Dot Point 8Investigate the structure and function of proteins in living things FunctionStructural- growth, repair and maintenance of tissues eg; collagen and actin

Enzymes- breaks down into a simpler structure or synthesise into something more complex eg; DNA polymerase.

Hormones- chemicals which are secreted into the blood and travel to target tissues where they cause a change in activity. Regulate body temperature eg; insulin

Storage- bind to certain substances and hold them in place eg; ferritin

Transport- bind to certain substances and carry them around the body eg; haemoglobin

Antibodies- involved in the immune system, react with antigens to help removes foreign particles from the body eg; IgA

Structure1. Primary- specific linear sequence of amino acids that make up a polypeptide chain2. Secondary – regular, repeated patterns of folding of the protein backbone eg; alpha

helix and beta sheet3. Tertiary- the overall folding of the entire polypeptide chain into a specific 3D shape4. Quaternary – occurs when a protein is made up of two or more polypeptides

Dot Point 9Conduct practical investigations to predict variations in the genotype of offspring by modelling meiosis, including the crossing over of homologous chromosomes, fertilisation and mutations

Dot Point 10Model the formation of new combinations of genotypes produced during meiosisAutosomalA pattern of inheritance and expression of genes, which are location on the autosomes

- If an organism has two different alleles (heterozygous) the dominant one will be expressed eg; Bb

- If and organism has two of the same alleles (homozygous) which ever one they have will be expressed eh; BB or bb

Sex-linkageRefers to the genes that are located on the sex chromosomes. It is about how the Y chromosome has less genes than the X chromosome, so that the male only has 1 copy for certain genes (on his 1 X chromosome)Co-dominance

Situation which both alleles are expressed in the phenotype, neither is dominant eg; roan cowIncomplete dominanceOccurs when one allele for a specific trait is not completely expressed over its paired allele, results in a third phenotype this is known as the blending of the alleles in the phenotype eg; snap dragonMultiple alleles There can be multiple alleles that determine a particular gene. Eg; rabbit fur colour or blood type in humans Pedigrees and Punnett squares Heterozygous non-pure breeding organism has two different alleles for a particular gene Homozygous pure breeding organism has two identical alleles for a particular geneTt = heterozygous tt= homozygous TT = heterozygous

T T

T TT TT

t Tt Tt

50% genotype = TT

50% genotype = Tt

100% phenotype of TALL

Dot Point 11 Collect, record and present data to represent frequencies of characteristics in a population, in order to identify trends, patterns, relationships and limitations in data

Examining frequency dataLooking at various data; height of yr 9 class

Analysing single nucleotide polymorphism SNP’s are single base pair variation in the genome a single nucleotide A, T, C or G is different. Results in genetic variation. It occurs in around 1 in 300 nucleotides thus, each human genome contains around 10 million SNP’s. Many SNP’s are in the introns, which do not ode for protein synthesis, therefore they do not affect human health. However, SNP’s that are in the Extron can affect human health as they do code for protein synthesis. Data from SNP’s can provide information about individuals therefore, we can provide personalised treatment

Dot Point 12

Investigate the use of technologies to determine inheritance patterns in a population usingDNA sequencing Involves determining the order of nucleotide bases in a stretch of DNA. The human genome project (HGP) was a large-scale collaborative project that aimed to sequence the 3 billion bases of the entire human genome and identify every human gene. Advantages of knowing the DNA sequence include; how we respond to medicines, how we act, behave, know genetic diseases, forensics. It identifies diseases, disorders, and evidence for evolution.

Sanga Method;- Goal is to separately identify the position of each nucleotide- Use 4 ‘special’ PCR’s- Each different tube contains a chain terminating nucleotide- Primer goes along allowing DNA polymerase to attach free nucleotides until it adds a

‘Guiane’ chain-terminating, resulting in the stopping of DNA synthesis- Do this for each of the bases- Run the gel to see how long or short- To determine order start from shortest fragment eg; if shortest is C then there would

be a G on the original strand.

Capillary electrophoresis;- Same but add fluorescent chain-terminating nucleotides- Laser and detector determines bases- Each base has its own colour - Whatever colour is visible is the complementary base

DNA profiling Process of analysing DNA variations for the purpose of identification. Looking at variations or similarities of DNA; finger printing, paternal and crimes. DNA variation = genetic markers = STR’s (short tandem repeats)

PCR; Polymerase chain reactionTechnique use to amplify DNA, involves copying DNA, occurs in test tubes, only a specific region is copied

1. Template DNA2. Free nucleotides 3. Heat-stable DNA polymerase4. DNA polymerase (enzyme)5. Primers – chemically synthesised DNA (they bind)6. Buffer – prevent change in the pH changes (liquid)

1. Denaturation;o Mixture is heated to 95 degreeso Separates into 2 strands = template

2. Annealing;

o Mixture cooled to 55 degreeso Allows primers to bind to template DNA

3. Extension;o Mixture heated to 72 degreeso DNA polymerase moves down template synthesising new DNA

4. Denaturation;o Heated back to 95 degreeso Separates DNA, prevents DNA synthesis o Process repeated again

Gel Electrophoresis; Fancy filtering system, which is used to separate and visualise DNA fragments according to their size. Uses fragments that have been amplified using PCR

Phosphate = negative charge

Sugar and nitrogenous bases = neutral

1. Prepare the set up o Pour liquid agarose gel into a mould o Insert well comb o Once set place in gel box o Immerse gel with buffer

2. Load DNA sample and DNA ladder o DNA sample is transferred into its own wello DNA ladder is added into well

3. Run the gelo Power is turned on (current runs through)o DNA will migrate through gel towards positive poleo Gel is a matrix (lots of tiny pores)o Small DNA fragments can fit through pores and move towards positive pores

quicker o Separates DNA according to size

4. Visualising the DNA fragmentso Add dye to stain DNA fragments

Dot Point 13Investigate the use of data analysis from a large-scale collaborative project to identify trends, patterns and relationship

- The use of population genetics data in conversation management - Population genetics studies used to determine the inheritance of a

disease or disorder- Population genetics relating to human evolution

Monogenic disease - Mutation in a single gene in all cells of the body - Prevalence = 10 in every 1000 births- The most common genetic differences in the genome are single base pair differences

called ‘single nucleotide polymorphisms’ (SNP’s)- Newborn screening in NSW for SNP’s associated with cystic fibrosis, urea’s cycle

disorders etc. (genetic conditions)- Provides early detection and improved treatment options

A trait that is controlled by multiple genes is said to be polygenic eg; eye colours. Predicting the phenotype of a polygenic trait is often difficult due to environmental influences.

Allele Frequency; is a measure of how common an allele is within a population = No. of copies of allele (G) in the population/no. of copies of the gene (G+g) in the population

Natural selection is the process by which individuals possessing traits that are advantageous for survival in their environmental live to reproduce

- Natural selection can alter allele frequency as those that are more dominant will have survived and out lived those that do not have that particular allele expressed. These alleles are survival of the fittest.

Sexual selection is a process whereby some traits become more common in the population due to mating partners being selected based on having such traits.

- Individuals with the ‘better looking traits’ are more likely to be chosen to mate with. Due to this, the offspring is more likely to have this trait. Therefore, over time this trait will become more dominant in the gene pool and more likely to have a higher allele frequency.

Gene flow is a term used to refer to changes in allele frequency due to new individuals entering a population or form individuals exiting a population

- Due to interbreeding, it will introduce new alleles to the population’s gene pool. This then changes the allele frequency therefore, increases genetic diversity. This will be more effective in a small population such as a zoo.

Genetic drift involves changes in allele frequency in the gene pool of a population due to random chance.

- Bottleneck effect; when a chance event causes a drastic decrease in the population size.

- Founder effect; when a new population is started by a small number of individuals who are not representative of the original population.