9.29.2 Maintaining a BalanceMaintaining a Balance • Most organisms are active in a Most organisms are active in a

limited temperature rangelimited temperature range • Plants and animals transport Plants and animals transport

dissolved nutrients and gases in a dissolved nutrients and gases in a fluid mediumfluid medium

• Plants and animals regulate the Plants and animals regulate the concentration of gases, water and concentration of gases, water and waste products of metabolism in waste products of metabolism in cells and in interstitial fluidcells and in interstitial fluid

EnzymesEnzymes

Identify the pH as a way of describing the Identify the pH as a way of describing the acidity of a substanceacidity of a substance

pH is a the amount of hydrogen ions pH is a the amount of hydrogen ions measured in a substance (solution) measured in a substance (solution)

pH of 7 is neutral e.g. water, 0-6 is pH of 7 is neutral e.g. water, 0-6 is acidic .e.g. lemon juice, 8-14 is acidic .e.g. lemon juice, 8-14 is basic .e.g. sodium bicarbonate basic .e.g. sodium bicarbonate

Explain why the maintenance of a constant Explain why the maintenance of a constant internal environment is important for optimal internal environment is important for optimal

metabolic efficiencymetabolic efficiency

Cells work best under their optimum Cells work best under their optimum conditions- right pH, temperature and the conditions- right pH, temperature and the best concentration. best concentration.

Enzymes control all metabolic processes in Enzymes control all metabolic processes in the body the body

Enzymes work in an environment where Enzymes work in an environment where they’re optimum temperatures and pH they’re optimum temperatures and pH conditions are met. At temperatures and pH conditions are met. At temperatures and pH values other than the optimum, the enzymes values other than the optimum, the enzymes fail to work as efficiently as they should or not fail to work as efficiently as they should or not at all. at all.

MetabolismMetabolism

Describe homeostasis as the process by which Describe homeostasis as the process by which organisms maintain a relatively stable organisms maintain a relatively stable

internal environmentinternal environment

In order to maintain maximum efficiency of In order to maintain maximum efficiency of an enzyme, the body must maintain a an enzyme, the body must maintain a stable/ constant internal environment. This stable/ constant internal environment. This is known as homeostasis.is known as homeostasis.

Homeostasis is the process by which the Homeostasis is the process by which the internal environment is kept within normal internal environment is kept within normal limits regardless, of the external limits regardless, of the external environmental conditions. This includes environmental conditions. This includes temperature, pH, gas levels, water and salt temperature, pH, gas levels, water and salt concentrations. This allows the enzyme’s concentrations. This allows the enzyme’s optimal conditions to be met and the body optimal conditions to be met and the body to work efficiently and kept stable to work efficiently and kept stable

HomeostasisHomeostasis

Explain that homeostasis consists of two Explain that homeostasis consists of two stages:stages:

Detecting changes from the stable stateDetecting changes from the stable state Counteracting changes from the stable stateCounteracting changes from the stable state Detecting changes-Detecting changes- Receptors detect changes to the normal internal Receptors detect changes to the normal internal

environment. e.g. sensory neurons in the skin environment. e.g. sensory neurons in the skin pick up a decrease or increase in temperature of pick up a decrease or increase in temperature of air surrounding the body.air surrounding the body.

Counteracting changes-Counteracting changes- After the receptors have detected these changes, After the receptors have detected these changes,

action is taken to counteract these so that action is taken to counteract these so that homeostasis is maintained. These are done by homeostasis is maintained. These are done by effectors. e.g. shivering to generate heat in effectors. e.g. shivering to generate heat in muscles.muscles.

Outline the role of the nervous system in Outline the role of the nervous system in detecting and responding to environmental detecting and responding to environmental

changeschanges

The co-ordinating system in humans is the nervous system.The co-ordinating system in humans is the nervous system. The nervous system consists of the central nervous system The nervous system consists of the central nervous system

(CNS) and the peripheral nervous system (PNS). The CNS (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal chord and the PNS consists of consists of the brain and spinal chord and the PNS consists of the sensory nerves and the effector nerves. When the the sensory nerves and the effector nerves. When the environmental temperature begins to exceed a comfortable environmental temperature begins to exceed a comfortable level for the body. The stimulus is detected and the sensory level for the body. The stimulus is detected and the sensory neurons send an impulse to the brain where the information is neurons send an impulse to the brain where the information is interpreted and a response is initiated. This response is then interpreted and a response is initiated. This response is then sent to the effectors.sent to the effectors.

Example- Temperature sensors in the skin detect the Example- Temperature sensors in the skin detect the temperature change (the stimuli) and a sensory neuron temperature change (the stimuli) and a sensory neuron conducts a nervous impulse to the hypothalamus found in the conducts a nervous impulse to the hypothalamus found in the brain. Nerve impulses pass this response from the receptors to brain. Nerve impulses pass this response from the receptors to effector neurons then onto effectors, such as blood vessels, effector neurons then onto effectors, such as blood vessels, sweat glands, endocrine glands and muscles. This is when we sweat glands, endocrine glands and muscles. This is when we shiver to try and generate heat.(counteract the stimuli)shiver to try and generate heat.(counteract the stimuli)

Identify the broad range of temperatures over Identify the broad range of temperatures over which life is found compared with the narrow which life is found compared with the narrow

limits for individual specieslimits for individual species

Life forms can found in the Life forms can found in the temperature range of –40ºC to 120ºCtemperature range of –40ºC to 120ºC

Majority of life forms are in the –2ºC Majority of life forms are in the –2ºC to 40ºC temperature range and is to 40ºC temperature range and is narrower for each individual species.narrower for each individual species.

Below 0ºC cell risk ice crystals Below 0ºC cell risk ice crystals forming and above 45ºC causes forming and above 45ºC causes them to denature.them to denature.

Compare responses of named Australian ectothermic Compare responses of named Australian ectothermic and endothermic organisms to changes in the ambient and endothermic organisms to changes in the ambient temperature and explain how these responses assist temperature and explain how these responses assist

temperature regulationtemperature regulation

EndothermsEndotherms Regulate body temperature using metabolism homeostasis. Regulate body temperature using metabolism homeostasis.

(birds and mammals) (birds and mammals) Insulation- control of blood flow (capillaries dilate to keep you Insulation- control of blood flow (capillaries dilate to keep you

cool), evaporation (humans sweat to keep cool), counter-cool), evaporation (humans sweat to keep cool), counter-current exchange (blood vessels placed together and chilled current exchange (blood vessels placed together and chilled bloody returning from veins gets heated up) and metabolic bloody returning from veins gets heated up) and metabolic activity (during hotter weather metabolism slows down {by activity (during hotter weather metabolism slows down {by product of this HEAT}) are ways that endotherms control their product of this HEAT}) are ways that endotherms control their body temperature.body temperature.

In hot conditions~ Example (1) Red kangaroo licks the inside of In hot conditions~ Example (1) Red kangaroo licks the inside of its paws, where skin is thinner, and blood supply is closer to the its paws, where skin is thinner, and blood supply is closer to the surface, so that heat can be easily dumped to the outside. surface, so that heat can be easily dumped to the outside. Evaporation from saliva promotes the loss of heat from the Evaporation from saliva promotes the loss of heat from the blood. Example (2) The large ears of the rabbit-eared-blood. Example (2) The large ears of the rabbit-eared-bandicoot provide a large surface area to pass excess heat bandicoot provide a large surface area to pass excess heat when it is burrowing during the heat of day and when it is when it is burrowing during the heat of day and when it is active at dusk.active at dusk.

Ectotherms-Ectotherms- Body temperature fluctuates, according to ambient Body temperature fluctuates, according to ambient

temperatures. (reptiles)temperatures. (reptiles) Hibernation- nocturnal activity, controlling exposure Hibernation- nocturnal activity, controlling exposure

and migration are ways that ectotherms control their and migration are ways that ectotherms control their body temperature.body temperature.

In cold conditions~ Example (1) magnetic termites In cold conditions~ Example (1) magnetic termites (Amitermes meridionalis) pack the walls of their (Amitermes meridionalis) pack the walls of their mounds with insulating wood pulp and align their mounds with insulating wood pulp and align their mounds north-south to maximise exposure to the sun mounds north-south to maximise exposure to the sun in the mornings and the evenings when the air is in the mornings and the evenings when the air is cooler and to minimise exposure during heat of day. cooler and to minimise exposure during heat of day. Example (2) Bogong moths are able to avoid their Example (2) Bogong moths are able to avoid their bodies freezing by supercooling their tissues. This bodies freezing by supercooling their tissues. This process involves reducing the temperature of the process involves reducing the temperature of the body fluids below their usual point of freezing and as body fluids below their usual point of freezing and as a result, ice crystals do not form and destroy the cells.a result, ice crystals do not form and destroy the cells.

Characteristics of ectotherms and endotherms:Characteristics of ectotherms and endotherms:Behavioural adaptations:Behavioural adaptations: MigrationMigration Hibernation and aestivationHibernation and aestivation ShelteringSheltering Nocturnal activityNocturnal activity Controlling exposureControlling exposureStructural adaptations:Structural adaptations: InsulationInsulation Physiological adaptations:Physiological adaptations: Metabolic activityMetabolic activity Control of blood flowControl of blood flow Counter-current exchangeCounter-current exchange EvaporationEvaporation

Animal BehaviourAnimal Behaviour

Identify some responses of plants to Identify some responses of plants to temperature changetemperature change

Plants can be damaged at temperature extremes Plants can be damaged at temperature extremes when enzyme structures are altered or membranes when enzyme structures are altered or membranes change their proteins. As many enzymes are involved change their proteins. As many enzymes are involved in photosynthesis and respiration temperature in photosynthesis and respiration temperature extremes can be a major problem.extremes can be a major problem.

In cold conditions, extracellular ice formation causes In cold conditions, extracellular ice formation causes dehydration. Some plants can tolerate temperatures dehydration. Some plants can tolerate temperatures as low as -50ºC by altering the solute concentrations as low as -50ºC by altering the solute concentrations and through lack of ice-nucleating sites in cells to and through lack of ice-nucleating sites in cells to prevent intracellular freezing.prevent intracellular freezing.

In hot desert conditions, plants develop a In hot desert conditions, plants develop a compromise between access to gases for compromise between access to gases for photosynthesis and access to gases for respiration by photosynthesis and access to gases for respiration by keeping their stomates open and cooling by keeping their stomates open and cooling by evaporation. This risks dehydration.evaporation. This risks dehydration.

Alpine PlantsAlpine Plants

Desert PlantsDesert Plants

In hot or cold plants may die but leave dormant In hot or cold plants may die but leave dormant seeds so to keep the flow going.seeds so to keep the flow going.

They may die above the soil but leave their roots They may die above the soil but leave their roots embedded in the ground so that they can keep embedded in the ground so that they can keep living when conditions are good.living when conditions are good.

Too high temperatures during flower formation Too high temperatures during flower formation may cause poor cropmay cause poor crop

Some seeds may only germinate after a fire.Some seeds may only germinate after a fire. Example (1)- eucalyptus leaves grow vertically to Example (1)- eucalyptus leaves grow vertically to

reduce exposure to the sun. Example (2)- reduce exposure to the sun. Example (2)- porcupine grass-sand in central Australia have porcupine grass-sand in central Australia have curled leaves that opens up after rain-exposing curled leaves that opens up after rain-exposing the stomata. In dry conditions the leaf curls up, the stomata. In dry conditions the leaf curls up, burying the stomata and reducing transpiration ... burying the stomata and reducing transpiration ... conserving water.conserving water.

Porcupine grassPorcupine grass

Identify data sources, plan, choose equipment or resources Identify data sources, plan, choose equipment or resources and perform a first-hand investigation to test the effect of:and perform a first-hand investigation to test the effect of:Increased temperatureIncreased temperatureChange in pHChange in pHChange in substrate concentrations on the activity of named Change in substrate concentrations on the activity of named enzyme(s)enzyme(s)

FACTORFACTOR EFFECT ON ENZYME ACTIVITYEFFECT ON ENZYME ACTIVITY

Increasing Increasing temperaturetemperature

Increases activity of the enzyme until Increases activity of the enzyme until it denatures. They have an it denatures. They have an optimum temperature.optimum temperature.

Change in pHChange in pH Depends on the enzyme. Each Depends on the enzyme. Each enzyme has they’re own optimum enzyme has they’re own optimum pH and it may denature.pH and it may denature.

Change in Change in concentration of concentration of the substratethe substrate

The higher the concentration the The higher the concentration the faster the reaction rate. The rate of faster the reaction rate. The rate of reaction is limited by the amount reaction is limited by the amount on enzyme present. (still works on enzyme present. (still works after saturation point)after saturation point)

Enzyme AffectorsEnzyme Affectors

Lipase investigation Effect on temperatureLipase investigation Effect on temperature Aim: to determine the relationship the relationship between Aim: to determine the relationship the relationship between

the effect of temperature and the activity of the enzyme, the effect of temperature and the activity of the enzyme, lipaselipase

Hypothesis: the enzyme lipase works best at a temperature Hypothesis: the enzyme lipase works best at a temperature of 35-40ºC.of 35-40ºC.

Apparatus:Apparatus: Full fat milkFull fat milk 8 test tubes8 test tubes Test tube rackTest tube rack 5% lipase solution5% lipase solution 0.05M sodium bicarbonate solution0.05M sodium bicarbonate solution PhenolphthaleinPhenolphthalein ThermometerThermometer Large beaker with waterLarge beaker with water Hot plateHot plate Measuring cylindersMeasuring cylinders StopwatchStopwatch Pipettes Pipettes

Method:Method: Place 50g of ice into a large beaker and test tubes 1 and 2 Place 50g of ice into a large beaker and test tubes 1 and 2

which contain 1ml of milk in each test tube. Record the which contain 1ml of milk in each test tube. Record the temperature.temperature.

Then add 11mls of sodium bicarbonate solution and 5 drops Then add 11mls of sodium bicarbonate solution and 5 drops of phenolphthalein to each test tube.of phenolphthalein to each test tube.

Add 1ml of lipase solution to test tube 1 and start timing. Add 1ml of lipase solution to test tube 1 and start timing. Note the colour changes of the solutions at I minute Note the colour changes of the solutions at I minute intervals for 5 minutes from the time of addition of Lipase. intervals for 5 minutes from the time of addition of Lipase. Note: test tubes 2,4,6 and 8 are controls (.i.e. they don’t Note: test tubes 2,4,6 and 8 are controls (.i.e. they don’t have the enzyme added to them.)have the enzyme added to them.)

Repeat steps 1-3 for test tubes 3 and 4 but this time use Repeat steps 1-3 for test tubes 3 and 4 but this time use water at room temperature approx. 20ºCwater at room temperature approx. 20ºC

Repeat steps 1-3 for test tubes 5 and 6 but this time use a Repeat steps 1-3 for test tubes 5 and 6 but this time use a water bath set at 35ºC water bath set at 35ºC

Repeat steps 1-3 for test tubes 7 and 8 but this time use a Repeat steps 1-3 for test tubes 7 and 8 but this time use a water bath set at 50ºCwater bath set at 50ºC

Repeat steps 1-6 three times and average your results.Repeat steps 1-6 three times and average your results. Collate data in a table and graph format.Collate data in a table and graph format.

N.B- for the experiment to be fair the following things are to N.B- for the experiment to be fair the following things are to be kept constant:be kept constant:

Lipase %: a higher lipase concentration will obviously speed Lipase %: a higher lipase concentration will obviously speed up the time it takes to break down the fat.up the time it takes to break down the fat.

Amount of milk/ lipase/ sodium bicarbonate/ water/ iceAmount of milk/ lipase/ sodium bicarbonate/ water/ ice Use the same stopwatch for each testUse the same stopwatch for each test Repeat the experiment 3 timesRepeat the experiment 3 times

Results:Effect of temperature on the enzyme, lipase

Time (mins):

Temp 0 1 2 3 4 5

Test tubes:

(ºC)

1- 0 DeepMilkypink

Deepmilky pink

Deep milky pink

Deep Milkypink

DeepMilkypink

Deepmilkypink

2- control 0 Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

3- 20 Deep pink

Deep pink

Pale pink

Lighter pink

Lighter pink

Lighter pink

4-control 20 Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

5- 35 Deep

pink

Pale pink

Lighter

pink

Lighter

pink

Lighter pink

White

6- control 35 Deep

Milky

pink

Deep

milky

pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

7- 50 Deep

milky

pink

Deep

milky

pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

8- control 50 Deep

milky

pink

Deep

milky

pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Conclusion: the milk solutions turn white when the Conclusion: the milk solutions turn white when the lipase and milk come in contact to produce fatty lipase and milk come in contact to produce fatty acids. Sodium bicarbonate makes the solution acids. Sodium bicarbonate makes the solution alkaline (pink) to start with but as more acids are alkaline (pink) to start with but as more acids are produced the pH drops and the solution turns produced the pH drops and the solution turns white. Lipase works best at a temperature of 35ºC white. Lipase works best at a temperature of 35ºC but beyond this denature, and becomes inactive. but beyond this denature, and becomes inactive. Active sites of enzymes have a particular shape Active sites of enzymes have a particular shape and because of this only one substrate molecule and because of this only one substrate molecule will fit into it. When an enzyme has lost its shape will fit into it. When an enzyme has lost its shape because of heat, the shape of the active site because of heat, the shape of the active site changes so a substrate molecule will no longer fit.changes so a substrate molecule will no longer fit.

Substrate ConcentrationSubstrate Concentration Aim: to determine the relationship the relationship Aim: to determine the relationship the relationship

between substrate concentration and the effect of the between substrate concentration and the effect of the enzyme, lipaseenzyme, lipase

Hypothesis: higher concentration milk will break down Hypothesis: higher concentration milk will break down more quickly into fatty acids by the action of the enzyme more quickly into fatty acids by the action of the enzyme lipase.lipase.

Apparatus:Apparatus:

Range of 3 different milk concentrationsRange of 3 different milk concentrations 6 test tubes6 test tubes Test tube rackTest tube rack 5% lipase solution5% lipase solution 0.05M sodium bicarbonate solution0.05M sodium bicarbonate solution PhenolphthaleinPhenolphthalein Large beaker Large beaker Hot plateHot plate Measuring cylindersMeasuring cylinders StopwatchStopwatch PipettesPipettes

The different milks are:The different milks are:

Type of milk:

Test Tube 1 and 2 1ml full fat milk

Test Tube 3 and 4 0.5ml of full fat milk and 0.5ml water

Test Tube 5 and 6 0.25ml of full fat milk and 0.75ml water

Method:Method: Set up a water bath at 35ºC with test tubes 1 and Set up a water bath at 35ºC with test tubes 1 and

22 Then add 11mls of sodium bicarbonate solution Then add 11mls of sodium bicarbonate solution

and 5 drops of phenolphthalein to each test tube.and 5 drops of phenolphthalein to each test tube. Add 1ml of lipase solution to test tube 1 and start Add 1ml of lipase solution to test tube 1 and start

timing. Note the colour changes of the solutions timing. Note the colour changes of the solutions at I minute intervals for 5 minutes from the time at I minute intervals for 5 minutes from the time of addition of Lipase. Note: test tubes 2,4 and 6 of addition of Lipase. Note: test tubes 2,4 and 6 are controls (.i.e. they don’t have the enzyme are controls (.i.e. they don’t have the enzyme added to them.)added to them.)

Repeat steps 1-3 for test tubes 3 and 4.Repeat steps 1-3 for test tubes 3 and 4. Repeat steps 1-3 for test tubes 5 and 6.Repeat steps 1-3 for test tubes 5 and 6. Repeat steps 1-5 three times and average your Repeat steps 1-5 three times and average your

results.results. Collate data in a table and graph format.Collate data in a table and graph format.

N.B- for the experiment to be fair the following N.B- for the experiment to be fair the following things are to be kept constant:things are to be kept constant:

Water bath at 37ºCWater bath at 37ºC Lipase %: a higher lipase concentration will Lipase %: a higher lipase concentration will

obviously speed up the time it takes to break obviously speed up the time it takes to break down the fat.down the fat.

Amount of milk/ lipase/ sodium bicarbonateAmount of milk/ lipase/ sodium bicarbonate Use the same stopwatch for each testUse the same stopwatch for each test Repeat the experiment 3 timesRepeat the experiment 3 times

Results:Effect of temperature on the enzyme, lipase

Time (mins): 0 1 2 3 4 5

Test tubes:

1- high conc. of milk

Deep pink

Pale pink

Lighter pink

Lighter pink

Lighter pink

White

2- control Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

3- med. Con. of milk

Deep pink

Deep pink

Pale pink

Lighter pink

Lighter pink

Lighter pink

4-control Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

5- low conc. of milk

Deep pink

Deep pink

Pale pink

Pale pink

Pale pink Pale pink

6- control Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Deep milky pink

Conclusion: the milk solutions turn white when Conclusion: the milk solutions turn white when the lipase and milk come in contact to produce the lipase and milk come in contact to produce fatty acids. Sodium bicarbonate makes the fatty acids. Sodium bicarbonate makes the solution alkaline (pink) to start with but more solution alkaline (pink) to start with but more acids are produced the pH drops and the solution acids are produced the pH drops and the solution turns white. The results indicate that the higher turns white. The results indicate that the higher the concentration of the substrate milk, the the concentration of the substrate milk, the quicker the reaction of the enzyme, lipase.quicker the reaction of the enzyme, lipase.

Gather, process and analyse information from Gather, process and analyse information from secondary sources and use available evidence to secondary sources and use available evidence to

develop a model of a feedback develop a model of a feedback mechanismSweatShiveringDecrease in mechanismSweatShiveringDecrease in

temperatureIncrease in temperatureDecrease in temperatureIncrease in temperatureDecrease in temperatureIncrease in temperatureHypothalamus (the temperatureIncrease in temperatureHypothalamus (the

brain)brain)

In a feedback system, the response alters the In a feedback system, the response alters the stimulus. Feedback can be negative (when the stimulus. Feedback can be negative (when the effect of the stimulus is reduced) or positive effect of the stimulus is reduced) or positive (when the effect of the stimulus is increased). (when the effect of the stimulus is increased). E.g. the control of hormone levels in the body, in E.g. the control of hormone levels in the body, in which an increase in the level of the hormone in which an increase in the level of the hormone in the blood decreases the output by the gland.the blood decreases the output by the gland.

A model of a feedback mechanism-A model of a feedback mechanism-

Analyse information from secondary sources to describe Analyse information from secondary sources to describe adaptations and responses that have occurred in Australian adaptations and responses that have occurred in Australian

organisms to assist temperature regulationorganisms to assist temperature regulationAustralianAustralianorganismorganism

EndotherEndotherm orm or

EctothermEctotherm

Adaptation or response to Adaptation or response to temperature regulationtemperature regulation

Red Red kangarookangaroo

EndotherEndothermm

Licks the inside of its paws, where Licks the inside of its paws, where skin is thinner, and blood supply skin is thinner, and blood supply is closer to the surface, so that is closer to the surface, so that heat can be easily dumped to the heat can be easily dumped to the outside. Evaporation from saliva outside. Evaporation from saliva promotes the loss of heat from promotes the loss of heat from the blood. the blood.

The rabbit-The rabbit-eared-eared-bandicootbandicoot

EndotherEndothermm

The large ears of the rabbit-eared-The large ears of the rabbit-eared-bandicoot provide a large surface bandicoot provide a large surface area to pass excess heat when it area to pass excess heat when it is burrowing during the heat of is burrowing during the heat of day and when it is active at dusk.day and when it is active at dusk.

Rabbit-Eared BandicootRabbit-Eared Bandicoot

Magnetic Magnetic termites termites (Amiterm(Amitermes es meridionameridionalis)lis)

EctotherEctothermm

Pack the walls of their mounds with Pack the walls of their mounds with insulating wood pulp and align their insulating wood pulp and align their mounds north-south to maximise mounds north-south to maximise exposure to the sun in the mornings exposure to the sun in the mornings and the evenings when the air is cooler and the evenings when the air is cooler and to minimise exposure during heat and to minimise exposure during heat of day. of day.

Bogong Bogong mothmoth

EctotherEctothermm

Able to avoid their bodies freezing by Able to avoid their bodies freezing by supercooling their tissues. This process supercooling their tissues. This process involves reducing the temperature of involves reducing the temperature of the body fluids below their usual point the body fluids below their usual point of freezing and as a result, ice crystals of freezing and as a result, ice crystals do not form and destroy the cells.do not form and destroy the cells.

Identify the form(s) in which each of the Identify the form(s) in which each of the following is carried in mammalian blood:following is carried in mammalian blood:Carbon dioxideCarbon dioxideOxygenOxygenWaterWaterSaltsSaltsLipidsLipidsNitrogenous wasteNitrogenous wasteOther products of digestionOther products of digestion

Substance

From To Form Carried by

Oxygen Lungs Body cells

Oxyhaemoglobin

RBC’s

Carbon Dioxide

Body cells

Lungs Hydrogen carbonate ions, bicarbonate ions

RBC’s and plasma

Water Digestive system and body cells

Body cells

Water molecules

Plasma

Salts Digestive system and body cells

Body cells

As ions in the plasma

Plasma

Lipids

Nitrogenous waste

Liver and body cells

Kidneys

Mostly as urea, sometimes ammonia or uric acid

Plasma

Other products of digestion

Digestive system and liver

Body cells

As separate molecules, .e.g. glucose, amino acids

Plasma

Explain the adaptive advantage of Explain the adaptive advantage of haemoglobinhaemoglobin

Haemoglobin-Haemoglobin- Large protein molecules found in RBC’sLarge protein molecules found in RBC’s Oxygen isn’t very soluble in water, which is why Oxygen isn’t very soluble in water, which is why

it’s carried in the haemoglobinit’s carried in the haemoglobin It increases the oxygen carrying capacity of RBC’s It increases the oxygen carrying capacity of RBC’s

by about four times.by about four times. Mammals require a constant and large supply of Mammals require a constant and large supply of

oxygen to produce enough heat to maintain oxygen to produce enough heat to maintain homeostasis.homeostasis.

HaemoglobinHaemoglobin

Supply can be adjusted to suit altitudeSupply can be adjusted to suit altitude Can bind to oxygen loosely-therefore release it Can bind to oxygen loosely-therefore release it

quicklyquickly And advantage to be carried in and RBC. If just And advantage to be carried in and RBC. If just

dissolved in plasma it would upset the osmotic dissolved in plasma it would upset the osmotic balance of the blood.balance of the blood.

The development of RBC’s without a nucleus leaves The development of RBC’s without a nucleus leaves more room for haemoglobin.more room for haemoglobin.

Compare the structures of arteries capillaries and veins in relation to their function

Artery Vein Capillary

Sketch

Description Thick, elastic,muscular walls

Biggerin diameter

than arteries, but their muscular wall is much

thinner.

One cell thick in diameter ... has a larger surface area to volume ratio.

Function Carry oxygen rich blood from lungs to the entire body

Carry deoxygenated blood back to the heart.

Exchange materials between blood and body cells.

Reason Blood is under pressure and needs to be pumped around to the body. The muscular walls expand and contract to push the blood through.

They are not under as much pressure and only travel one way. They are pushed up through valves.

Large SA:V allows for the easy exchange of nutrients (needed by cells and waste products)

Describe the main changes in the chemical composition Describe the main changes in the chemical composition of the blood as it moves around the body and identify of the blood as it moves around the body and identify

tissues in which these changes occurtissues in which these changes occur

The blood circulates through two systems in the body: The blood circulates through two systems in the body: the pulmonary system and the systemic system. the pulmonary system and the systemic system.

The pulmonary system-The pulmonary system- Blood flows from the heart to the lungs and then back Blood flows from the heart to the lungs and then back

to the heart. Blood travels in the pulmonary artery from to the heart. Blood travels in the pulmonary artery from the right ventricle to the lungs where carbon dioxide is the right ventricle to the lungs where carbon dioxide is released into the alveoli of the lungs. This is then released into the alveoli of the lungs. This is then ultimately released out of the body. Oxygen is picked ultimately released out of the body. Oxygen is picked up from the alveoli and diffused into the red blood cells up from the alveoli and diffused into the red blood cells to then be taken back to the heart. So via the to then be taken back to the heart. So via the pulmonary system, carbon dioxide is decreased and pulmonary system, carbon dioxide is decreased and oxygen levels increased.oxygen levels increased.

The systemic system-The systemic system- Blood flows from the heart to the rest of the body, Blood flows from the heart to the rest of the body,

except the lungs, and then returns. The left except the lungs, and then returns. The left ventricle pumps oxygenated blood to the rest of ventricle pumps oxygenated blood to the rest of the body, and as this blood circulates in the body, and as this blood circulates in capillaries, oxygen is delivered to the cells and capillaries, oxygen is delivered to the cells and carbon dioxide is picked up. Other waste carbon dioxide is picked up. Other waste products, such as urea, are also picked up from products, such as urea, are also picked up from the liver and transported in the blood to the the liver and transported in the blood to the kidneys. Blood flowing to the small intestines kidneys. Blood flowing to the small intestines collects the products of digestion and transports collects the products of digestion and transports them to the liver. Glucose is circulated in the them to the liver. Glucose is circulated in the blood stream to all cells in the body for blood stream to all cells in the body for respiration. Deoxygenated blood returns to the respiration. Deoxygenated blood returns to the heart via the inferior and superior vena cava.heart via the inferior and superior vena cava.

Outline the need for oxygen in living cells and Outline the need for oxygen in living cells and explain why removal of carbon dioxide from explain why removal of carbon dioxide from

cells is essentialcells is essentialOxygen-Oxygen- Needed for aerobic respiration to release energyNeeded for aerobic respiration to release energy A constant supply of oxygen is needed for the cells, A constant supply of oxygen is needed for the cells,

otherwise they’ll dieotherwise they’ll dieCarbon dioxideCarbon dioxide A bi-product of respiration is carbon dioxideA bi-product of respiration is carbon dioxide Increased carbon dioxide in blood stimulates the Increased carbon dioxide in blood stimulates the

breathing centre in the brain, which is why we pant breathing centre in the brain, which is why we pant after exercise. We take in more oxygen than we give after exercise. We take in more oxygen than we give out.out.

Carbon dioxide reacts with plasma (mostly water) to Carbon dioxide reacts with plasma (mostly water) to form carbonic acid (which is how it’s carried around form carbonic acid (which is how it’s carried around the body). If this becomes too much, the carbonic the body). If this becomes too much, the carbonic acid upsets the pH level-making it more acidic, acid upsets the pH level-making it more acidic, poisonous. However, we have special buffer systems poisonous. However, we have special buffer systems to stop this.to stop this.

Oxygen and Carbon Dioxide MoleculesOxygen and Carbon Dioxide Molecules

Describe current theories about processes Describe current theories about processes responsible for the movement of materials responsible for the movement of materials through plants in xylem and phloem tissuethrough plants in xylem and phloem tissue

Xylem-Xylem- The transpiration-cohesion-tension mechanism is The transpiration-cohesion-tension mechanism is

currently the theory that accounts for the ascent of currently the theory that accounts for the ascent of xylem sap. This sap is mainly pulled by transpiration xylem sap. This sap is mainly pulled by transpiration rather than pushed by root pressure. Cohesion is the rather than pushed by root pressure. Cohesion is the “sticking” together of water molecules so that they “sticking” together of water molecules so that they form a continuous stream of molecules extending form a continuous stream of molecules extending from the leaves down to the roots. Water molecules from the leaves down to the roots. Water molecules also adhere to the cellulose molecules in the walls of also adhere to the cellulose molecules in the walls of the xylem. As water molecules are removed by the xylem. As water molecules are removed by transpiration in the leaf, the next molecule moves transpiration in the leaf, the next molecule moves upwards to take its place, pulling the stream of upwards to take its place, pulling the stream of molecules continuously along. molecules continuously along.

XylemXylem

Phloem-Phloem- The pressure-flow mechanism is a model for The pressure-flow mechanism is a model for

phloem transport now widely accepted. phloem transport now widely accepted. The model has the following steps.The model has the following steps. Step 1: Sugar is loaded into the phloem tube from Step 1: Sugar is loaded into the phloem tube from

the sugar source, e.g. the leaf (active transport)the sugar source, e.g. the leaf (active transport) Step 2: Water enters by osmosis due to a high Step 2: Water enters by osmosis due to a high

solute concentration in the phloem tube. Water solute concentration in the phloem tube. Water pressure is now raised at this end of the tube.pressure is now raised at this end of the tube.

Step 3: At the sugar sink, where sugar is taken to Step 3: At the sugar sink, where sugar is taken to be used or stored, it leaves the phloem tube. Water be used or stored, it leaves the phloem tube. Water follows the sugar, leaving by osmosis and thus the follows the sugar, leaving by osmosis and thus the water pressure in the tube drops.water pressure in the tube drops.

The building up of pressure at the source end, and The building up of pressure at the source end, and the reduction of pressure at the sink end, causes the reduction of pressure at the sink end, causes water to flow from source to sink. As sugar is water to flow from source to sink. As sugar is dissolved in the water, it flows at the same rate as dissolved in the water, it flows at the same rate as the water. Sieve tubes between phloem cells allow the water. Sieve tubes between phloem cells allow the movement of the phloem sap to continue the movement of the phloem sap to continue relatively unimpeded.relatively unimpeded.

PhloemPhloem

Perform a first-hand investigation to Perform a first-hand investigation to demonstrate the effect of dissolved carbon demonstrate the effect of dissolved carbon

dioxide on the pH of waterdioxide on the pH of water

Changing pHChanging pHAim: to demonstrate the effect of dissolved carbon dioxide on Aim: to demonstrate the effect of dissolved carbon dioxide on

the pH of water.the pH of water.Apparatus:Apparatus: Hydrochloric acid (0.1M)Hydrochloric acid (0.1M) Calcium carbonate- poweredCalcium carbonate- powered Water Water Conical flask with side arm and connecting tubes Conical flask with side arm and connecting tubes BeakerBeaker StopperStopper Measuring cylinder Measuring cylinder Stop watchStop watch Universal indicator Universal indicator scalesscales

Method:Method: set up apparatus as shownset up apparatus as shown measure 30ml of hydrochloric acid and pour it into measure 30ml of hydrochloric acid and pour it into

the conical flaskthe conical flask Measure 40ml of water and place it in the beaker, Measure 40ml of water and place it in the beaker,

add a few drops of universal indicator and record add a few drops of universal indicator and record pH.pH.

Weigh 10g of calcium carbonate. Slowly pour into Weigh 10g of calcium carbonate. Slowly pour into flask and quickly cover with stopper. Once the flask and quickly cover with stopper. Once the calcium carbonate is in contact with acid begin calcium carbonate is in contact with acid begin timing. Make sure the tube is placed in water.timing. Make sure the tube is placed in water.

Record pH, measure at one minute intervals for five Record pH, measure at one minute intervals for five minutesminutes

Repeats steps 1-5 three times and record total Repeats steps 1-5 three times and record total average of resultsaverage of results

Repeat steps 1-5. Controlled reaction.Repeat steps 1-5. Controlled reaction. Repeat step 7 three times and record total average Repeat step 7 three times and record total average

of results.of results.

Results:

Experiment 1Experiment 2 Experiment 3

Time 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

pH 6.5 6.5 6 5.5 5.5 6.5 6 5.5 5 5 6 6 5.5 6 5

Conclusion:When carbon dioxide dissolves in water, it produced carbonic acid, which causes a decrease in pH, from pH of 6.5 to 5.5 in distilled water.

Perform a first-hand investigation using the light Perform a first-hand investigation using the light microscope and prepared slides to gather information microscope and prepared slides to gather information to estimate the size of red and white blood cells and to estimate the size of red and white blood cells and

draw scaled diagrams of eachdraw scaled diagrams of each

Analyse information from secondary sources to identify Analyse information from secondary sources to identify current technologies that allow measurement of current technologies that allow measurement of

oxygen saturation and carbon dioxide concentrations oxygen saturation and carbon dioxide concentrations in blood and describe and explain the conditions under in blood and describe and explain the conditions under

which these technologies are usedwhich these technologies are used

Biosensers-Biosensers- Made analysing blood gases quicker and more Made analysing blood gases quicker and more

accurate.accurate. A biosensor is a device with a transducer and a A biosensor is a device with a transducer and a

bioreceptor, usually one that recognises specific bioreceptor, usually one that recognises specific biochemical molecules. The bioreceptor reacts biochemical molecules. The bioreceptor reacts specifically with the substance to be detected and specifically with the substance to be detected and the transducer, which may be electrochemical, the transducer, which may be electrochemical, optical or thermal, converts the biochemical optical or thermal, converts the biochemical signal into an electrical signalsignal into an electrical signal

SensorsSensors A sensor is a device that translates a physical or A sensor is a device that translates a physical or

chemical property into an electrical signal that chemical property into an electrical signal that can be measured. The key component is the can be measured. The key component is the transducer or signal-converting element that transducer or signal-converting element that converts the poverty to be measured into a converts the poverty to be measured into a signal. Sensors usually use either optical or signal. Sensors usually use either optical or electrochemical technologies. Optical fibres are electrochemical technologies. Optical fibres are now replacing electrical wire for carrying signals now replacing electrical wire for carrying signals in many sensors.in many sensors.

Pulse oximeter (in hospitals) - a peg is attached Pulse oximeter (in hospitals) - a peg is attached to the finger of the patient where a light is to the finger of the patient where a light is transmitted through to the other side of the transmitted through to the other side of the finger. A photo detector on the other side finger. A photo detector on the other side measures how much light has been transmitted measures how much light has been transmitted through. The amount is directly proportional to through. The amount is directly proportional to the amount of oxygen in arterial blood.the amount of oxygen in arterial blood.

OximeterOximeter

Arterial Blood Gas AnalysisArterial Blood Gas Analysis Blood gas analysis, also called arterial blood gas (ABG) Blood gas analysis, also called arterial blood gas (ABG)

analysis, is a test which measures the amounts of analysis, is a test which measures the amounts of oxygen and carbon dioxide in the blood, as well as the oxygen and carbon dioxide in the blood, as well as the acidity (pH) of the blood.acidity (pH) of the blood.

An ABG analysis evaluates how effectively the lungs An ABG analysis evaluates how effectively the lungs are delivering oxygen to the blood and how efficiently are delivering oxygen to the blood and how efficiently they are eliminating carbon dioxide from it. The test they are eliminating carbon dioxide from it. The test also indicates how well the lungs and kidneys are also indicates how well the lungs and kidneys are interacting to maintain normal blood pH (acid-base interacting to maintain normal blood pH (acid-base balance). balance).

Done to assess respiratory disease and other Done to assess respiratory disease and other conditions that may affect the lungs, and to manage conditions that may affect the lungs, and to manage patients receiving oxygen therapy (respiratory patients receiving oxygen therapy (respiratory therapy). therapy).

The acid-base component of the test provides The acid-base component of the test provides information on kidney function.information on kidney function.

Blood gas analysis is performed on blood from an Blood gas analysis is performed on blood from an artery. It measures the partial pressures of oxygen and artery. It measures the partial pressures of oxygen and carbon dioxide in the blood, as well as oxygen content, carbon dioxide in the blood, as well as oxygen content, oxygen saturation, bicarbonate content, and blood pH.oxygen saturation, bicarbonate content, and blood pH.

Arterial Blood Analysis DeviceArterial Blood Analysis Device

Testing the partial pressure of oxygen is actually Testing the partial pressure of oxygen is actually measuring how much oxygen the lungs are measuring how much oxygen the lungs are delivering to the blood. Carbon dioxide is delivering to the blood. Carbon dioxide is released into the blood as a by-product of cell released into the blood as a by-product of cell metabolism. The partial carbon dioxide pressure metabolism. The partial carbon dioxide pressure indicates how well the lungs are eliminating this indicates how well the lungs are eliminating this carbon dioxide.carbon dioxide.

A related value is the oxygen saturation, which A related value is the oxygen saturation, which compares the amount of oxygen actually compares the amount of oxygen actually combined with hemoglobin to the total amount of combined with hemoglobin to the total amount of oxygen that the hemoglobin is capable of oxygen that the hemoglobin is capable of combining with.combining with.

Procedure-Procedure- Oxygen Concentration In BloodOxygen Concentration In Blood Sample of blood takenSample of blood taken Diffuses through a gas permeable membraneDiffuses through a gas permeable membrane This produces an electrochemical reactionThis produces an electrochemical reaction Which produces a currentWhich produces a current This current of proportional to oxygen This current of proportional to oxygen

concentrationconcentration Carbon Dioxide Concentration In BloodCarbon Dioxide Concentration In Blood Sample of blood is takenSample of blood is taken Diffused through a gas permeable membraneDiffused through a gas permeable membrane This changes the pH level in the solutionThis changes the pH level in the solution The change in pH is proportional to carbon The change in pH is proportional to carbon

dioxide concentration.dioxide concentration.

Analyse information from secondary sources to identify Analyse information from secondary sources to identify the products extracted from donated blood and discuss the products extracted from donated blood and discuss

the uses of these productsthe uses of these products

Donated blood- Broken down into:Donated blood- Broken down into: RBC’s- used to carry oxygen. Given to people with RBC’s- used to carry oxygen. Given to people with

anaemia whose people don’t make enough RBC’s or anaemia whose people don’t make enough RBC’s or people who’ve lost a lot of bloodpeople who’ve lost a lot of blood

WBC’s- used to combat infection. Given to people WBC’s- used to combat infection. Given to people with cancer of the blood e.g.- leukaemia. Used vary with cancer of the blood e.g.- leukaemia. Used vary rarely-usually antibiotics are usedrarely-usually antibiotics are used

Platelets-used for blood clotting. Given to people Platelets-used for blood clotting. Given to people with cancer of the blood because they don’t make with cancer of the blood because they don’t make enough plateletsenough platelets

Plasma-also used for blood clotting. Used to treat Plasma-also used for blood clotting. Used to treat people with haemophilia. Used to adjust osmotic people with haemophilia. Used to adjust osmotic pressure of blood and to pull fluids out of tissues.pressure of blood and to pull fluids out of tissues.

Immunoglobins-infection fighting parts in plasma. Immunoglobins-infection fighting parts in plasma. Used to treat people with difficulty fighting infection.Used to treat people with difficulty fighting infection.

Whole blood-only given when >20% of blood is lostWhole blood-only given when >20% of blood is lost

Donated Blood Platelets and PlasmaDonated Blood Platelets and Plasma

Analyse and present information from Analyse and present information from secondary sources to report on progress in secondary sources to report on progress in the production of artificial blood and use the production of artificial blood and use

available evidence to propose reasons why available evidence to propose reasons why such research is neededsuch research is needed

Artificial Blood-Artificial Blood- Need to be stored at room temp. and have a Need to be stored at room temp. and have a

prolonged shelf life; 3-4 weeksprolonged shelf life; 3-4 weeks World wide shortage of donor blood due to World wide shortage of donor blood due to

HIV/AIDS, Mad Cow Disease, new screening etcHIV/AIDS, Mad Cow Disease, new screening etc Need a safe and effective way to get a new blood Need a safe and effective way to get a new blood

source (considering there’s no donor blood source (considering there’s no donor blood anymore)anymore)

Used to:Used to: Increase plasma volume- artificial plasma expanders Increase plasma volume- artificial plasma expanders

are used for severe burns- so the blood can clot and are used for severe burns- so the blood can clot and healheal

Carry oxygen and carbon dioxide- not other Carry oxygen and carbon dioxide- not other substitutes for any other substitutes for any other nutrientnutrient yet yet

TypesTypes Perflurochemicals (PFC’s)Perflurochemicals (PFC’s) Can dissolve about 50 times more oxygen than blood Can dissolve about 50 times more oxygen than blood

plasmaplasma Cheap and free of biological materials- no risk of Cheap and free of biological materials- no risk of

infectioninfection To work must combine with other materials to mix To work must combine with other materials to mix

with the blood stream-usually lipids.with the blood stream-usually lipids. Haemoglobin- based oxygen carriers (HBOCs)Haemoglobin- based oxygen carriers (HBOCs) Oxygen bonds chemically but only dissolves in PFC’sOxygen bonds chemically but only dissolves in PFC’s Not contained in a membrane-don’t require blood Not contained in a membrane-don’t require blood

matchingmatching

PerflurochemicalsPerflurochemicals

PROBLEMSPROBLEMS Doesn’t stop haemoglobin from oxidising (doesn’t Doesn’t stop haemoglobin from oxidising (doesn’t

have the enzymes to stop it)- once oxidised it have the enzymes to stop it)- once oxidised it can’t carry oxygencan’t carry oxygen

Membrane protects the haemoglobin from Membrane protects the haemoglobin from degradation and toxic effects of haemoglobindegradation and toxic effects of haemoglobin

Alters blood flow through smallest vesselsAlters blood flow through smallest vessels Only stay in circulation for 20-30 hours, instead of Only stay in circulation for 20-30 hours, instead of

RBC’s-100daysRBC’s-100days If in an accident you’ll usually be given saline If in an accident you’ll usually be given saline

(sodium chloride- same concentration as blood (sodium chloride- same concentration as blood and other tissues- 0.9%) OR dextrose- 4% glucose and other tissues- 0.9%) OR dextrose- 4% glucose and 0.18% saline solution.and 0.18% saline solution.

Choose equipment or resources to perform a Choose equipment or resources to perform a first-hand investigation to gather first-hand first-hand investigation to gather first-hand

data to draw transverse and longitudinal data to draw transverse and longitudinal sections of phloem and xylem tissuesections of phloem and xylem tissue

Xylem carries water and minerals upward from Xylem carries water and minerals upward from the root hairs (where the water comes from). Due the root hairs (where the water comes from). Due to capillarity and the transpiration stream. They to capillarity and the transpiration stream. They are dead tissues and narrow.are dead tissues and narrow.

Phloem carries minerals produced by Phloem carries minerals produced by photosynthesis; mainly sugar, up and down the photosynthesis; mainly sugar, up and down the plant.plant.

Symplastic Loading- materials travel in the Symplastic Loading- materials travel in the cytoplasm from the mesophyll cells to the sieve cytoplasm from the mesophyll cells to the sieve element (the phloem) through plasmodesmata. element (the phloem) through plasmodesmata. This means a lot of plasmodesmata are required.This means a lot of plasmodesmata are required.

Apoplastic Loading- nutrients travel through the Apoplastic Loading- nutrients travel through the cell walls until they get to the sieve element. cell walls until they get to the sieve element. They then cross the cell membrane into the They then cross the cell membrane into the phloem. The sieve element becomes loaded with phloem. The sieve element becomes loaded with sugars (nutrients) and dumps them into a sink sugars (nutrients) and dumps them into a sink cell. This keeps pressure of the phloem constant.cell. This keeps pressure of the phloem constant.

Explain why the concentration of water in Explain why the concentration of water in cells should be maintained within a narrow cells should be maintained within a narrow

range for optimal function.range for optimal function. Water concentration in cells is critical for most living Water concentration in cells is critical for most living

organisms. It must remain constant as slight changes organisms. It must remain constant as slight changes may lead to cell death. This is because:may lead to cell death. This is because:

Water is essential for life. Water is the solvent for all Water is essential for life. Water is the solvent for all the metabolic reactions in living cells. It takes part the metabolic reactions in living cells. It takes part directly in many of them such as photosynthesis and directly in many of them such as photosynthesis and is formed as a product in is formed as a product in manymany others including others including respiration.respiration.

Living cells function best in an isotonic environment Living cells function best in an isotonic environment (one in which the solute concentration is the same (one in which the solute concentration is the same both inside and outside the cell). They are very both inside and outside the cell). They are very sensitive to changes in solute concentration and as sensitive to changes in solute concentration and as consequence may lose or take in large amounts of consequence may lose or take in large amounts of water by osmosis.water by osmosis.

Changes in concentration of water in the cell will Changes in concentration of water in the cell will affect the concentration of dissolve substances, which affect the concentration of dissolve substances, which in turn can affect the metabolic functionin turn can affect the metabolic function

Explain why the removal of wastes is Explain why the removal of wastes is essential for continued metabolic activity.essential for continued metabolic activity.

Wastes products are constantly being formed as a Wastes products are constantly being formed as a result of metabolic processes that occur in cells. result of metabolic processes that occur in cells. However, the removals of these wastes are However, the removals of these wastes are essential because:essential because:

Some of the wastes build up as toxins and could Some of the wastes build up as toxins and could poison the cells. For example:poison the cells. For example: Carbon dioxide Carbon dioxide Nitrogenous wastes Nitrogenous wastes

If allowed to accumulate in cells and tissues, these If allowed to accumulate in cells and tissues, these wastes could disrupt or slow down metabolic wastes could disrupt or slow down metabolic reaction ratesreaction rates

Different animals excrete different wastes productsDifferent animals excrete different wastes products Aquatic animals, fish and invertebrates mostly Aquatic animals, fish and invertebrates mostly

excrete ammonia. Ammonia is toxic, but can be excrete ammonia. Ammonia is toxic, but can be released continuously and directly into the water released continuously and directly into the water and is quickly dispersedand is quickly dispersed

Terrestrial animals excrete nitrogenous waste as Terrestrial animals excrete nitrogenous waste as either urea or uric acid. This is because terrestrial either urea or uric acid. This is because terrestrial animals need to conserve water by converting animals need to conserve water by converting ammonia into less toxic forms and excrete it ammonia into less toxic forms and excrete it periodically. Urea is soluble and is released in periodically. Urea is soluble and is released in urine while uric acid is almost insoluble and non-urine while uric acid is almost insoluble and non-toxic.toxic.

Identify the role of the kidney in the excretory Identify the role of the kidney in the excretory system of fish and mammals.system of fish and mammals.

Kidney is an organ of filtration, reabsorption and Kidney is an organ of filtration, reabsorption and secretion. The primary role of the kidneys is secretion. The primary role of the kidneys is osmoregulation, the regulation of the water and osmoregulation, the regulation of the water and salt concentrations in the body.salt concentrations in the body.

The kidney forms urine by removing wastes such The kidney forms urine by removing wastes such as nitrogenous wastes, salts, other unwanted as nitrogenous wastes, salts, other unwanted metabolic products and excess water, from the metabolic products and excess water, from the blood. The kidney maintains the balance of salts blood. The kidney maintains the balance of salts and water in the body, and so has a vital role in and water in the body, and so has a vital role in homeostasis.homeostasis.

NB: The structural and functional unit of the NB: The structural and functional unit of the kidney is the nephron. There are approximately 1 kidney is the nephron. There are approximately 1 million nephrons in each human kidney. Each million nephrons in each human kidney. Each nephron is made up of glomerulus and tubules.nephron is made up of glomerulus and tubules.

Nephron ProcessNephron Process

Explain why the processes of diffusion and Explain why the processes of diffusion and osmosis are inadequate in removing dissolved osmosis are inadequate in removing dissolved

nitrogenous wastes in some organisms.nitrogenous wastes in some organisms.

The processes of diffusion and osmosis are The processes of diffusion and osmosis are inadequate for removal of wastes because:inadequate for removal of wastes because:

Diffusion is too slow and non-selective of Diffusion is too slow and non-selective of solutessolutes

Diffusion would mean all salts would be Diffusion would mean all salts would be eliminated along with glucose and vitamins; eliminated along with glucose and vitamins; whereas the body needs to retain some whereas the body needs to retain some salts and nutrientssalts and nutrients

Osmosis would mean that wastes would Osmosis would mean that wastes would stay in the body and that water would leavestay in the body and that water would leave

OsmosisOsmosis

Distinguish between active and passive Distinguish between active and passive transport and relate these to processes transport and relate these to processes

occurring in the mammalian kidney.occurring in the mammalian kidney.

In the kidneys both forms of transport are used in In the kidneys both forms of transport are used in regulating the body fluid composition.regulating the body fluid composition.

Passive transport requires no energy. Passive Passive transport requires no energy. Passive transport occurs in filtration and in the osmosis of transport occurs in filtration and in the osmosis of water back into the blood.water back into the blood.

Active transport requires energy from metabolism Active transport requires energy from metabolism (ATP). Active transport occurs in the secretion of (ATP). Active transport occurs in the secretion of substances into the nephron, the active transport substances into the nephron, the active transport of nutrients back into the blood, and the selective of nutrients back into the blood, and the selective reabsorption of salts required by the body. These reabsorption of salts required by the body. These processes require energy, as they would have to processes require energy, as they would have to go against the concentration gradient.go against the concentration gradient.

Explain how the processes of filtration and Explain how the processes of filtration and reabsorption in the mammalian nephron reabsorption in the mammalian nephron

regulate fluid composition.regulate fluid composition. Filtration and reabsorption occurs in the nephron.Filtration and reabsorption occurs in the nephron. Filtration involves the removal of substances from Filtration involves the removal of substances from

blood if they are small enough to be forced blood if they are small enough to be forced through the glomerulus and into the Bowman’s through the glomerulus and into the Bowman’s capsule. The glomerulus acts like an ultra filter capsule. The glomerulus acts like an ultra filter and particles that are too large such as proteins and particles that are too large such as proteins cannot pass through the Bowman’s capsule.cannot pass through the Bowman’s capsule.

Filtered blood then moves along the tubules. Filtered blood then moves along the tubules. Useful substances such as water, glucose, amino Useful substances such as water, glucose, amino acids, vitamins, hormones and inorganic salts are acids, vitamins, hormones and inorganic salts are reabsorbed through diffusion and osmosis.reabsorbed through diffusion and osmosis.

Hence, the processes of filtration and Hence, the processes of filtration and reabsorption regulate body fluid composition as it reabsorption regulate body fluid composition as it perform the complex balancing of retaining perform the complex balancing of retaining essential substances and removing toxic wastes essential substances and removing toxic wastes from blood to maintain homeostasis.from blood to maintain homeostasis.

Outline the role of the hormones, aldosterone Outline the role of the hormones, aldosterone and ADH (anti-diuretic hormone) in the and ADH (anti-diuretic hormone) in the

regulation of water and salts levels in blood.regulation of water and salts levels in blood.

Adolsterone is a steroid hormone produced by the Adolsterone is a steroid hormone produced by the adrenal cortex of the kidney. Its role is to maintain a adrenal cortex of the kidney. Its role is to maintain a balance of water and salts in the body. It stimulates balance of water and salts in the body. It stimulates the nephron to increase the concentration of the nephron to increase the concentration of sodium ions leading to a decrease in reabsorption of sodium ions leading to a decrease in reabsorption of potassium ions and more water diffusing into blood potassium ions and more water diffusing into blood at the nephron. This causes a rise in blood pressure at the nephron. This causes a rise in blood pressure and volume.and volume.

Anti-diuretic Hormone (ADH) is a hormone produced Anti-diuretic Hormone (ADH) is a hormone produced by the hypothalamus and stored in the pituitary by the hypothalamus and stored in the pituitary gland that stimulates the nephrons to absorb more gland that stimulates the nephrons to absorb more water. This acts to decrease urine volume.water. This acts to decrease urine volume.

Antidiuretic Hormone ActionAntidiuretic Hormone Action

Define enantiostasis as the maintenance of Define enantiostasis as the maintenance of metabolic and physiological functions in metabolic and physiological functions in

response to variations in the environment and response to variations in the environment and discuss its importance to estuarine organisms discuss its importance to estuarine organisms

in maintaining appropriate salt in maintaining appropriate salt concentrations.concentrations.

Enantiostasis is the maintenance of metabolic Enantiostasis is the maintenance of metabolic and physiological functions in response to and physiological functions in response to variations in the environment.variations in the environment.

To estuarine organisms the maintenance of salt To estuarine organisms the maintenance of salt concentrations is important. Many of the concentrations is important. Many of the organisms cannot control salt and water levels, organisms cannot control salt and water levels, instead they exhibit enantiostasis in order to instead they exhibit enantiostasis in order to survive the daily change in salinity.survive the daily change in salinity.

Ways in which some estuarine organisms function Ways in which some estuarine organisms function to overcome daily change in salinity:to overcome daily change in salinity:

Fast-swimming organisms can move away from Fast-swimming organisms can move away from area with high salinityarea with high salinity

Molluscs can close their shells Molluscs can close their shells Bottom dwellers burrow or dig deep into mud or Bottom dwellers burrow or dig deep into mud or

sandsand Halophytes tolerates changes in salinity by having Halophytes tolerates changes in salinity by having

a special mechanism to control their level of slata special mechanism to control their level of slat Saltbushes have special salt excretion glands on Saltbushes have special salt excretion glands on

their leavestheir leaves Some mangroves excrete salt from special glands Some mangroves excrete salt from special glands

in their leavesin their leaves

MangrovesMangroves

Describe adaptations of a range of terrestrial Describe adaptations of a range of terrestrial Australian plants that assist in minimizing Australian plants that assist in minimizing

water losswater loss

Some adaptations to limit water loss that Australian Some adaptations to limit water loss that Australian plants exhibit include:plants exhibit include:

Hard or thick waxy cuticles on leaves, such as Hard or thick waxy cuticles on leaves, such as eucalyptseucalypts

Hairy leaves, stems and even flowers to restrict air Hairy leaves, stems and even flowers to restrict air flow and evaporation, such as alpine groundselflow and evaporation, such as alpine groundsel

Leaves that droop or roll to reduce the exposure of Leaves that droop or roll to reduce the exposure of stomates, such as spinifexstomates, such as spinifex

A tough, woody structure that prevents plants wilting A tough, woody structure that prevents plants wilting even when they lose water, such as alpine groundseleven when they lose water, such as alpine groundsel

Small leaves, such as saltbushesSmall leaves, such as saltbushes Leaves with a reduced number of stomatesLeaves with a reduced number of stomates Widely spreading or deep root systems to obtain Widely spreading or deep root systems to obtain

more water, such as mulgamore water, such as mulga

Perform a first-hand investigation of the Perform a first-hand investigation of the structure of a mammalian kidney dissection, structure of a mammalian kidney dissection, use a model or visual resource and identify use a model or visual resource and identify regions involved in the excretion of waste regions involved in the excretion of waste

products.products.

Gather, process and analyse information from Gather, process and analyse information from secondary sources to compare the process of secondary sources to compare the process of renal dialysis with the function of the kidney.renal dialysis with the function of the kidney.

Kidney function Renal dialysis

A natural body process An artificial process replacing damage kidney

Performed by two fist-sized organs

Performed by a large machine attached to a variety of computer and other equipment

Removes wastes continuously Performed repeatedly under hospital conditions (two or three times each week, for several hours each time)

Varies output automatically, depending on concentrations of wastes in blood

Concentrations of substances in blood and dialysis fluid are monitored by computers so that most wastes are removed during treatment

Wastes may be removed by both diffusion and active transport

Wastes removed by diffusion

Present information to outline the general use Present information to outline the general use of hormone replacement therapy in people of hormone replacement therapy in people

who cannot secrete adolsterone.who cannot secrete adolsterone.

Aldosterone is used to regulate water and salt Aldosterone is used to regulate water and salt reabsorption. When aldosterone cannot be reabsorption. When aldosterone cannot be secreted, the excretory system will not be as secreted, the excretory system will not be as efficient. The person cannot maintain homeostasis efficient. The person cannot maintain homeostasis and become severely dehydrated. The hormone and become severely dehydrated. The hormone replacement is taken on a regular basis, to maintain replacement is taken on a regular basis, to maintain balance of salts. The main artificial substitute for balance of salts. The main artificial substitute for adolsterone is called fludrocortisone. Appropriate adolsterone is called fludrocortisone. Appropriate hormone replacement therapy can enable patients hormone replacement therapy can enable patients to manage symptoms such as fluid retention and to manage symptoms such as fluid retention and high blood pressure and lead normal lives.high blood pressure and lead normal lives.

Analyse information from secondary source to Analyse information from secondary source to compare and explain the differences in urine compare and explain the differences in urine concentration of terrestrial mammals, marine concentration of terrestrial mammals, marine

fish and freshwater fish.fish and freshwater fish.

Type of animal

Urine components and concentration

Explanation

Terrestrial mammal

(e.g. bilby)

Concentrated urine, usually composed of urea, salts, other wastes and water.

Excess salts and other wastes are excreted dissolved in water. Water needs to be conserves, urine produced is concentrated. Nitrogenous wastes present as urea - it is less toxic than ammonia and can be present in higher concentration

Freshwater fish

(e.g. native bass)

Large quantities of very dilute urine, usually composed of ammonia, small amounts of salts and large amount of water

Freshwater fish absorb large volumes of water through gills and mouth thus much water must be excreted. Ammonia is suitable - sufficient water to dilute it. Salts - low concentration in fresh water, therefore fish take up salts from water as replacement.

Marine fish(e.g. whiting)

Small quantities of concentrated urine, usually composed of trimethylamine oxide, other wastes and small volumes of water

Marine fish constantly lose water - high salt environment. Excrete little water in concentrated urine containing high levels of non-toxic trimethylamine oxide and salts.

Use available evidence to explain the Use available evidence to explain the relationship between the conservation of relationship between the conservation of water and the production and excretion of water and the production and excretion of

concentrated nitrogenous wastes in a range of concentrated nitrogenous wastes in a range of Australian insects and terrestrial mammals.Australian insects and terrestrial mammals.

Type of nitrogenous wastes (uric acid or urea) Type of nitrogenous wastes (uric acid or urea) and its high concentration enable these and its high concentration enable these organisms to reduce the amount of water they organisms to reduce the amount of water they lose to remove wastes. This helps them to lose to remove wastes. This helps them to conserve water in harsh and dry environments.conserve water in harsh and dry environments.

Process and analyse information from Process and analyse information from secondary sources and use available evidence secondary sources and use available evidence to discuss processes used by different plants to discuss processes used by different plants

for salt regulation in saline environments.for salt regulation in saline environments. Mangrove:Mangrove: Shrubby tree that grows in estuariesShrubby tree that grows in estuaries Its roots have a layer of cells that actively restrict the Its roots have a layer of cells that actively restrict the

movement of salt into xylem vesselsmovement of salt into xylem vessels Able to excrete salt through the underside of its leaves. Salt Able to excrete salt through the underside of its leaves. Salt

crystals accumulate on leaves and so salt is lost when older crystals accumulate on leaves and so salt is lost when older leaves fall from plantleaves fall from plant

Saltbush:Saltbush: Tolerate salinity levels that kill most other plantsTolerate salinity levels that kill most other plants Excrete large amount of salt through their leavesExcrete large amount of salt through their leaves In general plants removed salt for regulation by:In general plants removed salt for regulation by: Salt can be redirected towards drying leaves, so when drop Salt can be redirected towards drying leaves, so when drop

off the plants, the salt is removedoff the plants, the salt is removed Salt excretion glands actively excrete salt by allowing it to Salt excretion glands actively excrete salt by allowing it to

crystallize and be blown or washed awaycrystallize and be blown or washed away Osmotic adjustmentOsmotic adjustment

Perform a first-hand investigation to gather Perform a first-hand investigation to gather information about structures in plants that information about structures in plants that

assist in the conservation of water.assist in the conservation of water.