Biology 2 1st Quarter Reviewer

HIERARCHY OF BIOLOGICAL ORGANIZATION

1. Biosphere - Environments on earth inhabited by life

2. Ecosystem- Abiotic & biotic interaction (specified area)

3. Community- Array of organisms inhibiting ecosystems

4. Population- Individuals of a species (specified area)

5. Organism- Individual living things

6. Organ System- Group of organs performing a specific &

vital function of the body7. Organ

- Group of tissues; carries out a smaller function in the body

8. Tissue- Group of similar cells

9. Cell - Fundamental unit of structure and function

MULTICELLULARITY

a. LIMITATION OF SIZE Max size limit exceeded >> multicellularity Multicellularity ↑ dependency ↑; loss of cell

singularity Bigger cell size leads to decrease in:

* exchange of substances * diffusion (high low concentration; no energy used / passive transport)* Surface Area : Volume (SA:V)

Solutions to the SA:V problem: *↑ surface area & ↓ volume; more surface area means more contact points thus more substances are absorbed * Increase rate of supply (↑ concentration of nutrients)

b. MOVEMENT TOWARDS MULTICELLULARITY Theories:

Symbiotic Theory (prokaryotes Invaded primitive eukaryotic cells)

Syncytial Theory (cells developed internal membrane partitions)

Colonial Theory (symbiosis of organisms of the same species; The Volvocine series)

c. MODES OF REPRODUCTION Isogamy – Same gametes Heterogamy / Anisogamy - different gametes;

different size (sperm is smaller than the egg); both are motile

Oogamy (Specialized heterogamy) – sperm is flagellated; egg is not motile >> able to store more energy >> bigger egg cell >> more space to store food

CHLAMYDOMONAS Unicellular flagellate Reproduction: Isogamy No communication No colony

GONIUM No polarity to colony Small colony Intracellular communication (pass the message)

PANDORINA Colony in 1 layer High dependence (colony dies when disrupted) High communication (coordinate flagellate

movement) EUDORINA

Specialization occurred Reproduction: evolved to Anisogamy

PLEDORINA Has special reproductive cells Division of labor Reproduction: Anisogamy; egg started to

become non-motile VOLVOX

Reproduction: evolved to oogamy Cell will live even when taken out of its colony Intracellular communication No polarity to colony Has special reproductive cells

d. EVIDENCE OF EVOLUTION

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Isogamy Anisogamy Heterogamy Unicellular to colonial life (cells are able to

specialize; increase in number of cells) Increase in interdependence & division of labor Less female gametes produce >> healthier eggs

(nutrients & best genes are given to the egg)

e. ADVANTAGES OF MULTICELLULARITY Increase in organism size; ↑ SA:V Permits cell specialization

f. DISADVANTAGES OF MULTICELLULARITY Interdependence (one cell dies, many cells are

greatly affected; organism may even die)

PLANT TISSUES

Plant Organization

Root system - Growth towards gravity- Generally below the ground; consists of

plant roots - Root: epidermis, cortex, stele, pith

Shoot system - Growth away from gravity along the axis- Generally above the ground - Consists of the stem and leaves - Flowers: modified shoot system

a. Meristematic Tissue Main function is mitosis (to increase number of

cells) Do not specialize but is the precursor cell (turns

into wither dermal, ground or vascular tissue)

_______________________________________ Three types:

1. Apical Shoot Apical Meristem

- Region of embryonic cells near the dome; tip od all shoots is the source of primary growth

- Three primary meristems: > Protoderm – Dermal Tissue> Ground Meristem – Ground Tissue> Procambrium – vascular tissue

Root Apical Meristems - Apical meristem near all root tips give rise

to the protoder, ground meristem and procambium

- Transitional meristems give rise to the root primary tissue systems: epidermis, ground tissues and vascular tissues

2. Lateral Lateral Meristems

- Produce secondary growth > Vascular cambium – secondary vas. tissue> Cork cambium – periderm

Increases growth horizontally / girth of plant

3. Intercalary Plants without vascular cambium (grasses) Growth regions that occur at the base of nodes Only found in monocots

(monocots – scattered vascular bundle; dicots – circular vascular bundle)

Primary growth of roots - Root cap protects the delicate meristems as

the root elongates through the soil; secretes mucus that lubricates the soil

- 3 zones of cells > Division – meristems (mitotsis) > Elongation – bigger cell; more energy; more resources > Differentiation – any plant cell has the ability to differentiate

b. Dermal Tissues For protection Prevents desiccation (dehydration / water loss) Epidermis – top most layer Cuticle – a waxy layer secreted by epidermal

cells of stems and leaves; prevents water loss, invasion of pathogens and diffusion of gasses

Periderm – composes the outer bark Epidermal modifications:

- Root hairs: absorption of water- Guard cells: form the tiny opening called

the stomata

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- Glands: modified cells containing oils or other substances for secretion

c. Ground Tissues Basically for support Parenchyma

- Basic tissue type- Simple tissue composed of spherical shapes- Large, have thin primary walls - Living metabolizing tissue (at functional

maturity) - Functions: for photosynthesis & respiration,

storage, and wound healing & regeneration Collenchyma

- A simple tissue found beneath the epidermis in young stems and in large veins of leaves

- Function: for support - Found uniformly throughout te plant - Elongated cells that have unevenly thick

walls (ends are thicker)- Alive at functional maturity - Cells fill up the spaces

Sclerenchyma - Walls are very thick and are placed

uniformly around the entire margin of the cell wall

- Function: protection - Dead at functional maturity because it

becomes the bark of the tree or hard outer covering of nuts

d. Vascular Tissues Conduct water and solutes Function: transport Xylem

- Conducts water and minerals from the roots to the leaves

- Water always moves upward due to the environment

- Make up the wood - Composed of:

1. Vessel elements> movement of water can be transverse or longitudinal > elongated cells with secondary walls

> dead at functional maturity > thick in diameter

2. Tracheid> elongated cells with secondary walls > dead at functional maturity > thin in diameter, more tapered > movement of water is longitudinal

Phloem - Moves solutes (sugars) - Physiologically dictates sugar transport - Alive at functional maturity because they

have to digest the food - Composed of:

1. Sieve tube > transports the sugars

2. Companion cells > connected to the sieve tube > loads the sieve tube

e. Essential Nutrients Hydroponic structure

- used to determine which of the minerals are actually essential nutrients

Macronutrients - Elements required by plants in relatively

large amounts Micronutrients

- Elements needed by plants in relatively small amounts

ANIMAL TISSUES

a. Epithelial Tissue Lines organs and covers the body (skin) For protection: pathogens are unable to

penetrate the body Outer part is exposed to air or internal fluid,

inner part is composed of the basement membrane

Cells are tightly packed Types according to shape:

1. Squamous 2. Cuboidal 3. Columnar

Types according to cell size 1. Simple – one cell thick 2. Stratified – more than 1 layer thick

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3. Pseudostratified (for columnar only) – each cell still touches the basement membrane

b. Connective Tissue For binding and support Cells are widely separated from each other Attaches skin to the muscle Cells are embedded in an extracellular matrix Cells secrete the matrix (either soft or sold) Lose and dense connective tissues

- Act as padding under skin - Loose: loose weave of fiber; widespread

packing material; holds organs in place Bone and cartilage

- Made up of cells in a hard extracellular matrix; for support

- Bone: collagen fibers in calcium salts - Rigid parts of the skeleton - Cartilage: rubbery collagenous matrix- Flexible part of the skeleton

Blood - Made up of cells in a liquid plasma matrix - Used in transport

Adipose tissue - For storage, insulation and padding

c. Muscular Tissue For movement / contraction; produces heat in

the body Skeletal muscle

- Unbranched fibers- Striated- Attached to bones- Voluntary movements of the body - 5 nuclei; peripherally loacted

Smooth muscle- Spindle shaped cells- Unstriated- Contraction of other internal organs - Digestive tract, arteries, bladder- Centrally located nucleus (uninucleate)

Cardiac muscle - Branced fibers - Striated- Heart (involuntary muscle)- Uninucleate

- Bifurcated - Looks like shorts ! haha

d. Nervous Tissue Senses stimuli and transmits signals called nerve

impulses from one part to another Consists of a cell body and long extensions

called dendrites (towards cell) and axons (towards another cell)

DIGESTION

Leads to the breakdown of the important substances for the body to grow and develop

a. 4 MACROMOLECULES Macromolecule (broken down into) – digested in Carbohydrates (sugars) – mouth Proteins (amino acids) – stomach Fats (lipids) – small intestine Nucleic Acids (nucleotides) – small intestine

* macromolecules we take in are not the same as the macromolecules our body makes; they are not the same when they reach the stomach

b. EVOLUTIONARY EVIDENCE Fats – you are able to store energy Compartmentalization (annelids developed a

digestive tract) Modes of feeding (more to eat and digest) Mutualistic relationships (humans & E coli)

c. INTRACELLULAR VS EXTRACELLULAR DIGESTION Intracellular

Within food vacuoles Unicellular organisms and poriferans

Extracellular Outside of the cell Fungi digest outside the boy then absorb

the digested material Incomplete & complete digestion

d. INCOMPLETE VS COMPLETE DIGESTION

Incomplete Single opening for food entrance and waste

exit

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Gastrovascular cavity of cnidarians (link to complete digestion)

Gastrodermis – with specialized digestive cells

Hydrolysis of macromolecules Complete

Two different openings for food entrance and waste exit

Complexity varies in each phyla Extracellular hydrolysis of food Specialized compartments

e. MODES OF FEEDING Suspension / filter feeders – most affected by

the environment; ↓ development Substrate feeders – live in their food Fluid feeders – ex. Humming birds & mosquitos Bulk feeders – most complex alimentary canal

HUMAN DIGESTION (4 STAGES)

1. INGESTION Phagocytosis – general term for taking in food

through pseudopods Mechanical digestion starts: chewing

_______________________________________ After mechanical digestion, food particles get

smaller thus increasing its SA:V Easier digestion

After chemical digestion, SA:V increases even more. Chains are cut so that there are more ends enzymes can work on when breaking down the food

Denaturation – breaking down of bonds (protein only)

2. DIGESTION a. Mouth

- Both mechanical and chemical digestion begin

- Mechanical: chewing to break down food - Chemical: enzymes are used to breakdown

food* SALIVARY GLADS produce SALIVA which contains SALIVARY AMYLASE which acts on STARCH to produce MALTOE

- Bolus – resulting ball of food from the actions of the teeth, tongue and saliva

- Enzyme – catalyst (speeds up digestion)

b. Pharynx - Crossroad of food and air - Where the bolus enters the esophagus - Epiglottis – seal to prevent food from

entering air passages - Glottis – frame

c. Esophagus - Upper portion: striated muscle - Lower portion: smooth muscle - - moves the bolus from the pharynx o the

stomach through peristalsis (movement of smooth muscle in the alimentary canal to the large intestine)

- Goblet cells – lines esophagus, releases mucus that covers the bolus for easier movement through the esophagus

d. Stomach - Storage and digestion of food - Sphincter – regulates movement of the bolus

and the chime Cardiac – prevents backflow Pyloric – regulates entrance of acidic chime

to the small intestine - Carnivore has a larger stomach compared to

a herbivore - Mechanical: peristalsis (closed sphincters)- Chemical: digestion of proteins- Chief cells – produce pepsinogen - Parietal cells – produce HCL

* HCL activates pepsinogen to become pepsin (positive feedback) * (+) feedback: reactant ↑ product ↑* (-) feedback : reactant ↑ product ↓

- rapid mitotic activity (mucus lining protects the stomach because when the stomach becomes acidic, mucus is digested first)

e. Small Intestine - Main organ of digestion and absorption

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- The longest because it enables more absorption in the body

- Duodenum (digestion); jejunum and ileum (absorption)

DIGESTION OF MACROMOLECULES

Carbohydrate digestion: - Starch, glycogen, etc is further digested- Pancreatic amylase breaks it down - Maltase: splits maltose into its glucose units - Diasaccharides: absorbed by intestinal

epithelium Protein digestion:

- Trypsin and chymotrypsin: breakdown pepsin

- Trypsin: activates procarboxypeptidase and chymotrypsinogen

- Dipepsidase: split small peptidase - Carboxypeptiase: breakdown polypetides in

its carboxyl end - Aminopeptidase: breakdown peptidase in

its nitrogenous end - Enteropeptidase: activates trypsin - Intestinal enzymes: aminopeptidase &

enteropeptidase Fatty acid digestion

- Bile salts: emulsify (increase in SA) undigested fats in the duodenum

- Lipase: digests fat molecules Nucleic acid digestion

- Nucleases: hydrolyzes nucleic terminals o (Exo – terminals/ends; endo – within)

3. ABSORPTION Villus – folds found in the small intestine; each

is connected to a blood vessel and lacteals Microvillus – ↑ SA:V; thus ↑absorption

HORMONES THAT REGULATE DIGESTION

Gastrin: stimulated by gastric juices; low pH; ↑ secretion of gastric juice; (+) feedback

Enterogastrones: enzymes in the duodenum Cholecystokinin (CCK): stimulates by fats and

amino acids; stimulates the gall bladder to

release bile which emulsifies fats so that lipase can act on it

Secretin: stimulated by the acidic chime; stimulates pancreas to release bicarbonates; protects small intestine* If chime contains a lot of fat, the duodenum releases other enzymes to slow down digestion in the stomach

f. Large Intestine / Colon - Main function: reabsorption of water- Cecum – small pouch that has different

functions - Appendix – small cecum found in man (ceptic

tank)- Rectum – temporarily store feces- Feces – waste formed after digestion;

compactness depends on the amount of water reabsorbed

- Internal bacteria: E coli - Low peristalsis, high absorption of water

4. EXCRETION Feces leaves the rectum

NUTRITION

a. Adequate diet includes: Fuel (chemical energy from carbs/ fats) Organic materials Essential nutrients (substances the animal

cannot make) b. Balancing the fuel

Homeostatic mechanism (glucose conversion) Fats – most amount of ATP

c. Caloric imbalance Undernourishment – caloric deficiency Over nourishment – excessive caloric intake Malnourishment – deficient in any essential

nutrient

d. Essential nutrients Amino acids – protein deficiency Fatty acids – (unsaturated) deficiencies are rare Vitamins – fat soluble vitamins when intake is

high; required in relatively small amounts

Amica !

PLANT TRANSPORT

a. Transport Mechanisms Passive Transport

- Does not use up any energy- Diffusion: high to low concentration

Active Transport - Uses up energy- Transportation from low to high

concentration or when molecules are too big to transport by passive transport

Bulk Transport - Transportation of large amount of

substances

* Energy is in the form of ATP

b. Plant Transport Tissues Xylem – transports water

Tracheid – tapered, long, thinner diameter Vessel Element – less tapered, short, wider

diameter Phloem

Companion Cells – loads the sugar into the sieve tube

Sieve Tube – transports sugar (singular: tube member)

c. Movement of water: Symplast vs Apoplast

Plasmodesmata – opening in the cell Apoplast – casparian strip (wax) is present No casparian strip >> less build-up of pressure

d. Three scales of plant transport Intracellular

- Epidermal cells Short distance: Cell to cell

- For tissue and organs

Long Distance: Xylem and Phloem

e. Effects of differences in water potential For survival

- Plants must balance uptake & loss of water Osmosis

- Determines uptake or loss of water by a cell - Affected by solute concentration & pressure

Water potential - Amount of water a system has- Determined by the concentration of water - Determines direction of the flow of water

* water flows from high concentration to low concentration (direction); affected by both solute concentration and pressure

* If a flaccid cell is placed in an environment with high concentration of solute, the cell will plasmolyze

* If a flaccid cell is placed in an environment with high concentration of water, the cell will become turgid

_________________________________________________________________________________________________________________________________________________________________

Terms: * Water Potential – amount of water a system has

* High water potential – ↑ water concentration* Low water potential – ↓water concentration

* Tonicity – concentration of the solute* Hypertonic – ↑ salt concentration* Hypotonic – ↓salt concentration * Isotonic – equal amount of salt and water

* Flaccid – normal cell * Plasmolyze – plant cell loses water* Turgid – plant cell gains water * Stele – group of xylem tissues inside the root

f. Bulk flow in long distance transport Bulk flow

- Movement of fluid in the xylem and phloem is driven by pressure differences at opposite ends of the xylem vessels and the sieve tube

THE XYLEM SAP

g. Root Pressure Positive pressure (push)

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Upward movement of xylem sap because of a push (force exerted because of high amount of water in the roots)

Movement is from the soil to the roots because the soil has a higher concentration of water

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Small plants at night: Guttation dew (through active transport)

h. Transpiration-Cohesion-Tension Mechanism Negative pressure (pull) Transpiration – evaporation of water from a

plant to the atmosphere * Because plant has high water potential compared to the atmosphere (in transpiration)

Cohesion – similar cells Adhesion – dissimilar cells

* a tree uses both root pressure and TCTM except root pressure is not its main type of transport for root pressure is for shorter distances

THE PHLOEM SAP

i. Pressure flow Process

1. Photosynthetic cell makes the sugars 2. Metabolism of Sieve tube / Companion cells

loads the sugars in to the sieve tube 3. Sieve tube becomes hypertonic; there is a

decrease in water potential 4. Because of the high water potential in the

xylem and low water potential in the phloem (sieve tube), water flows into the sieve tube, increasing pressure

5. The water and sugar solution moves from high pressure to low pressure(phloem sap where cell is metabolizing; can go in all directions)

6. Water goes back into the xylem because of loss of water in the xylem

7. Cycle continues Active transport – photosynthetic cell to the cell

(sugars are too big so active transport is used)

ANIMAL TRANSPORT

Functionally connect the organs of exchange with the body cells

Not all animals have transport systems (animals such as poriferans/sponges, cnidarians and flatworms; they use diffusion)

Most invertebrates have a gastrovasular cavity / circulatory system for internal transport

Double circulation - Depends on the anatomy and pumping cycle

of the heart - Organism should have 2 atria

a. Gastrovascular Cavity Digestion and circulation Presence of 2-cell thick body walls Only the inner layer is exposed to food; outer

layer receives food through diffusion

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Both layers are bathed with fluid* Planarians and other flatworms also have a gastrovascular cavity; their body shape ensures the efficient transport of food

b. Open vs. Closed Circulatory System

* both overcome the limits of diffusion * 3 basic components:

1. Circulatory fluid (blood) 2. Tubes (blood vessels) 3. Pumping organ (heart)

Open circulatory system - Bathed organs that need nutrients - No distinction between blood and interstitial

fluid (called hemolymph) - Sinuses – interconnected spaces that

surround organs - Heart contraction: pumps hemolymph to the

sinuses and other organs (they are bathed) - Heart relaxation: hemolymph is drawn back

to the heart through the ostia

* Interstitial fluid – allows diffusion of substances into the cell; acts as a ladder

Closed circulatory system - Blood just goes around; confined in the

blood vessels and is distinct from the interstitial fluid

- Exchange of materials of through diffusion

c. Single vs Double circulation Single circulation

- Seen in fish (blood vessels are in between the muscle; when muscles contract, blood vessels are squished, allowing blood to flow)

Double Circulation - Ensures that blood pressure is retained- Depends on the anatomy and pumping cycle

of the heart; must have 2 atria (heart receives blood twice)

d. Vertebrate Phylogeny Reflected in adaptations of the gastrovascular

system Cardiovascular system: presence of heart &

vessels High metabolic rate: more complex (more

energy is needed to convert fat into energy) Low metabolic rate: less complex Frog vs mouse: mouse has a more complex

vascular system for it is endothermic Atrium: receives blood; thin muscle layer Ventricle: pumps blood; thickest muscle layer

due to function * left ventricle (thicker) pumps blood to the whole body; right ventricle pumps blood to the lungs / respiratory system

Vessels

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Arteries: carries blood away from the heart; thickest muscle layer where the ventricle pumps blood; pulmonary artery has valves as well that regulate entrance and exit of blood

Arterioles: smaller arteries Venules: Veins: carries blood back to the heart; between

muscle tissues; contains valves Capilliaries: thinnest muscle layer so diffusion is

made possible and easy; 2 layers Branching – more cells are reached

e. Fish heart 2 main chambers 1 atrium 1 ventricle Gill circulation: loading of oxygen to the blood Systemic circulation: oxygen is unloaded from

the blood

f. Frog and other amphibian hearts 3 chambered heart Forked artery (pulmocutaneous & systemic

circulation) Double circulation (restores blood pressure) Mixing of blood Reptiles: presence of ridge in ventricle 4

chambered heart (Seen as evolution) Right ventricle: deoxygenated blood Left ventricle: oxygenated blood

g. Mammals, birds and crocodilians 4 chambered heart Left side: oxygen rich Right side: oxygen poor No mixing of blood

Slow velocity/ acceleration low pressure low force (Force = mass x acceleration)

Double circulation in mammals depends on the anatomy and pumping cycle of the heart

h. Human heart Cardiac cycle – complete pumping and filling Systole – contraction Diastole – relaxation Cardiac output – volume of pumped blood into

systematic circuit per minute * heartrate: number of beats per minute * Stroke volume: amount of blood pumped per contraction

Amica !