2013 HSC COURSE

Feedback mechanism in which the response opposes the stimulus. 

e.g. increase in blood glucose ---> high blood glucose detected by pancreas ---> pancreas secretes insulin ---> glucose stored as glycogen ---> decrease i nblood glucose 

RBC: ~ 7-8 micrometres (x10^-6) disc shaped with a collapsed interior in order to maximise SA for movement of materials. No nucleus 

WBC: ~ 15 micrometres. Deformed shape with a nucleus 

1. endotherms require a lot of energy to maintain constant internal body temperature 

2. ectotherms enzymes function over a much wider temperature range than endotherms 

.Metabolism = all reactions and processes in a cell 

enzymes control all metabolic processes 

each process / reaction is controlled by a specific enzyme

May be used to anabolise or catabolise 

Enzymes lower the energy required to start chemical reactions 

Enzymes are not used up in the process

enzyme activity will generally increase with substrate concentration untill a V max is reached 

That is when all active sites are occupied 

Aim: To draw scale longitudinal and transverse diagrams of xylem and phloem

Materials: 1x cellery, 1x microscope, 2x glass slides, 1x minigrid, 1x compass, 1xpencil 1x red dye 1x 1/2 litre of water, 1x 600mL beaker 1x pipette 2x coverslips

Risk: the microscope is heavy and may cause injury to feet if dropped. As such carry the microscope with both hands holding the base

Method: 1. soak the cellery in the red dye for an hour 2. use the minigrid to estimate the field of view for 400x magnification (working way up from 10x magnification) and record 3. slice thin longitudinal and transverse sample of the cellery and prepare a wet mount for each 4. place one of the wet mounts on the microscope and make way from 10x magnification up to 400x 5. use the field of view and its diameter to estimate and draw the wet mount sample 6. repeat steps 4 and 5 for the other wet mount 

Endotherms - maintain constant internal temperature regardless of external temperature. include mammals and birds 

Ectotherms - limited ability to maintain constant internal temperature independant of external temperature. Include reptiles, amphibians, fish and invertebrates 

Part of the phloem tissue, arranged end to end.

No nucleus or organelles - kept alive by compagnion

cells. Linked to each other by plasmodesmata 

spinifex hopping mouse - terrestiral mammal - urea - lives in a very arid environement

grass hopper - terrestrial insect - uric acid - arid environment

Allows the exchange of materials between the blood and tissues

Links veins to arteries 

1 endothelium cell thick to maximise exhchange of materials back and forth 

small lumen to keep up pressure 

Very thing and permeable 

carry deoxygenated blood away from the blood at low pressure 

composed of thin layers of endothelium lining, smooth muscle and connective tissue 

Contains valves to prevent backflow 

large lumen to reduce resistance to flow

Terrestrial - water conservation is key therefore cannot excrete large volumes of water / concentrated urine

Marine - Lose a lot of water via osmosis (as surrounding environment is much saltier) therefore excrete a very low volume of water / highly concentrated urine. Also gain salts by diffusion which are secreted by specific glands 

Freshwater - gain a lot of water via osmosis  (surrounding environment has lower salt concentration) therefore urine very dilute / excrete large volumes of water. Lose salts by diffusion which are absorbed in the gut and by active transport in the gills 

Red kangaroo - endothermic - licks paws to draw away heat, vasodialates to remove heat, lies in shade during the day, has blood vessels very close to the skin in forearms

Blue tongued lizard  - endothermic - uses shelter to lose / absorb heat, may remain inactive, basks in the sun

Wombat - endothermic - basks in the sun, large SA to V ratio, burrows for heat loss / gain, diurnal activity, may slow metabolism to 1/3 

Eastern brown snake: diurnal, seek shelters to lose, become active in the cooler part of the day, basks in the sun  to gather heat.

Aim: to test the effects of a change in temperature on the enzyme catalyse's reaction rate 

hypothesis: the reaction rate will be highest at 40 degrees celcius

risk: H202 is corrosive. Therefore safety specs and gloves should be worn

independant variable: temperature 

dependant variable: reaction rate (height of foam)

controlled variables: time, pH, substrate concentration, enzyme concentration 

control: H202, liver and water 

Materials: 1x waterbath at 40 degrees 1x waterbath at 80 degrees 1x thermometer 1x icecream container filled with ice 24 x testtubes 1x liver piece 1x H202 1x pipette 1x detergent 1x stopwatch

Method: 1. cut liver into 0.5cm^2 pieces 2. place 10mL of H202 into a testtube and 0.5cm^2 piece of liver into another 3. acclimatise both to 0 degrees celcius 4. add 3 drops of detergent to the H202 5. combine the H202 and detergent with the liver and record height of foam after 30 seconds 6. repeat steps 2-5 2 more times 7. repear 2-6 with temperatures: room temp, 40 degrees and 80 degrees 8. record results and average height for each in a table

1. changes in the physical conditions in the environment e.g. climate, wind, rainfall

2. changes in the chemical conditions in the environment e.g. pH, salinity

3. Competition for resourses e.g. food, water, mates

Carry oxygenated blood away from the heart at high pressure 

composed of thick elastic walls of endothelium lining, smooth muscle and connective tissue

small lumen to keep blood at high pressure

Mechanism for the transport of organic substances in the phloem from source to sink 

e.g. sugar 

1. sugar is loaded into the phloem by active transport from the source

2. water enters the phloem from the xylem by osmosis 

3. pressure buildup forces sugar and water from source to sink 

4. sugar is actively transported from phloem to sink 

5. water reenters xylem by osmosis

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the nervous system is composed of the central nervous system (the brain and the spine) which instructs responses from changes from normal state / conditions and the peripheral nervous system (sensory and effector neurones) which detect the change from normal condition and sends messages to the CNS (from the receptor) and back (to the effector)

Maintainance of metabolic and physiological functions in response to variations in the environment - rather that keeping conditons constants conforms to conditons. 

Occurs in osmoconformers 

Each enzyme has an optimum pH to work in order to achieve optimum reaction rate 

pHs on either side of this optimum interfere with the enzyme bonds so that it is no longer able to bond with substrate (denatures)

sex linked disease where the blood in unable to clot properly 

x - linked - therefore more predominantly expressed in males 

does not follow normal mendellian ratios 

Enzymes are large globular 3D proteins (polypeptide chains of amino acids) with precise shapes 

The precise shapes means that there is only one reaction that a certain enzyme may assist 

Bonds with substrate at the active site 

Both are inadequate in the removal of nitrogenous wastes as 

1. Osmosis is related only to the moment of water 

2. both are too slow as they are passive processes 

3. Diffusion is unable to select specific solutes

At extreme temperatures plants may be damages due to enzyme denaturing, non enough enzyme activity, change in membrane properties, formation of ice crystals etc...

responses to temperature change include: 

1. transpiration - evaporation of water from plant leaves take heat with it cooling the plant down 

2. wilding / tugor reponse - a loss in the rigidity of non - woody parts of plants reduces the SA of leaves exposed to the sun thereby cooling the plant down

3. leaf orientation 

4. organic antifreeze - prevents the formation of ice crystals in cells etc

5. dormancy - growth and development is temporarly stopped to slow metabolism and conserve energy 

6. rolled leaves - decrease SA exposed to the sun

contamination: Artificial no chance, donated e.g. 1 in 750000 Hep B

patients: Artificial all patients, donated not all - jehovahs witnesses and patients with immune responses

supplies: artificial potentially unlimited, donated limited

types: artificial type 0- universal donated all types 

shelf life: artificial no shelf life, donated e.g. RBCs 42 days 

Problems with artificial blood: 

1. clinical trials indicated adverse effects including increased heart pressure and increased risk of heart attack 

2. donated blood cost ~$6 a gram artificial $200-$1000

3. social concern regarding the privitisation of artificial blood 

Thomas hunt morgan discovered sex linked inheritance after experimenting / observing eith the inheritance of eye colour in fruit flies 

Results did not follow mendellian ratios 

After crossing the offspring of a red eyes male and a white eyed female the results were 50% Red ♀ 25% Red ♂ 25% White ♂

Showed that the inheritance of red / white eys was sex linked ( x linked)

table showing all genotype combinations in a croos between parents with known genotypes 

predicts likelyhood of certain genotypes and phenotypes 

pea plants 

1. easy to control breeding 

2. observing easly observable characteristics 

3. large numbers (repitions = reliablity)

4. use of 'true breeding' lines at start 

5. pea plant reproduces quickly 

6 multiple generations 

Carried out a large number of cross polinations between varieties of pure breeding lines of garden peas over sucessive generations 

examined traits such as height, flower colour, pea colour, wrinkled prea vs smooth etc...

F1 generation resulted in all of one type in a catagory e.g. cross of tall and short plants resulted in F1 being all tall

F2 generation showed a 3:1 ratio 

From this worked Mendel deduces the existance of discrete hereditary factors (genes), the principle of segregation and the principle of intependant assortment

Aims: to test the effects of a change in substrate concentration on an enzyme lipase's reaction rate

Hypothesis: Reaction rate will be at its highest when substrate concentration is at its highest

Risk: Sodium carbonate is hazardous. As such safety specs and gloves should be worn 

Materials: 1x 15mL of each milk type (skim, lite, full) 3x testubes 1x pH probe 1x data logger 1x waterbath at ~40 degrees celcius 1x  9mL lipase solution 1x pipette  1x 65 mL sodium carbonate 1x thermometer

Independant: substrate concentration 

dependant: reaction rate (change in pH) 

controlled variables: temperature, enzyme concentration, time

Control: same 3 milk types with water and sodium carbonate

Method: 1. put 5mL of each milk type into seperate testtubes 2. add 7m sodium carbonate to each 3. acclimatise milks to 37 degrees celcius  4. add 1mL lipase solution to each 5. record data using pH probe and data logger 6. repeat 2 more times. 7. record all results in a table.

feedback mechanisum where the response furthers the stimulus 

e.g. number of cattle stampeding ---> increasing panic level in the herd ---> number of cattle stampeding increasing 

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