Stage 6 HSC Biology:
Maintaining the Balance 1
1. Outline the chemical makeup of enzymes and use a diagram to represent how enzymes are specific
(use terms like substrate, lock and key). Name two chemical enzymes important in the human body.
2. Identify three key features which may influence the rate of enzyme action and describe the optimum
range in humans for two of them.
3. Homeostasis refers to the balance in the human body. With reference to processes in the human body,
explain how our body responds to changes in temperature to maintain balance.
4. What is feedback in humans? Use an example of feedback mechanisms to explain their role in
homeostasis.
5. List some of the variables organisms must control to maintain a constant internal environment.
Nominate two and explain the importance of each variable.
6. Australian animals vary in methods of regulating temperature. Distinguish between ectotherms and
endotherms using named examples. Describe one adaptation for thermoregulation for each animal and
how it assists in thermoregulation.
7. Australian mammals vary in methods of regulating temperature. For named examples describe a
behavioural, a physiological and a structural adaptation to heat regulation.
8. Plants also respond to temperature changes in their environment. Identify responses of two named
Australian plants to temperature change.
9. The source of internal heat in endothermic organisms is cellular respiration. Describe cellular
respiration using appropriate equations.
10. In humans we often observe red cheeks and ears after strenuous exercise. With reference to blood
vessels and temperature maintenance, explain these observations.
11. The relative amount of food intake measured for a lizard and a monkey with reference to their body
mass shows a greater intake by the monkey. Explain this trend with reference to your understanding
of metabolism.
12. Indicate a behavioural advantage for a named Australian ectotherm which assists in temperature
regulation.
13. Plants have specific responses to temperature change and may have adaptations to assist their survival
in a range of environments. Describe two adaptations which allow plants to survive in extreme
environments and two responses to drastic changes in temperature.
14. Describe a behavioural adaptation for a named Australian ectotherm which assits it in temperature
regulation.
15. Outline the two steps in the maintenance of homeostasis.
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Stage 6 HSC Biology:
Maintaining the Balance 2
1. Compare the structure of veins, arteries and capillaries relating their structure to the role of each in the
circulatory system.
2. Explain the difference between haemoglobin and oxyhaemoglobin and describe three roles of
haemoglobin in the circulatory system.
3. Describe the effect of too much carbon dioxide building up in the blood plasma using a relevant
chemical equation as part of your response.
4. Outline the adaptive advantage of human blood possessing haemoglobin.
5. Athletes are often tested for performance enhancing drugs. Discuss why an athlete who is found with a
drug which increases the production of haemoglobin may be guilty of trying to enhance performance.
6. List the main products transported to and from body tissues and identify for each product the form it is
carried in the bloodstream.
7. Contrast the systemic and pulmonary systems of circulation in humans in terms of the path involved
and the pump that controls them.
8. Use a diagram to explain the movement of substances into and out of a capillary with reference to what
process drives the movement.
9. Transport in mammals is via a system of veins, arteries and capillaries. They move a variety of
substances from one place to another. Considering only oxygen, carbon dioxide, nitrogenous wastes
and digestive products, construct a table which shows the form each substance is carried in, where it is
taken from and taken to and what structure carries it.
10. Whole blood transfusion only takes place in the event of major trauma. Select three specific
components which may be extracted from human blood and describe their role as products for
transfusion.
11. The current system of blood donation is often unable to keep up with demand. Describe an alternative
being considered as a blood substitute and assess its usefulness.
12. Identify the changes that may occur to blood as it moves through the human liver.
13. An organism excretes its nitrogenous wastes in the form of crystals. Describe some environmental
pressures that may cause this physiological process and indicate some other adaptations which may
assist.
14. Compare the size, shape and function of the two types of blood cells.
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Stage 6 HSC Biology:
Maintaining the Balance 3
1. Filtration in the human kidney occurs in the glomerulus and the Bowman’s capsule. List the substances
that are removed during this filtration.
2. Draw and label a generalised structure of a filtering unit in the human kidney which identifies the main
area for filtration, reabsorption and secretion.
3. With reference to substances involved explain the difference between the processes of filtration,
reabsorption and secretion.
4. The movement of substances into and out of cells is normally driven by osmosis and diffusion.
Contrast these processes with the movement of substances into and out of the filtering units in the
kidneys.
5. Distinguish between active and passive transport and identify regions where each process occurs in the
nephron.
6. Outline the main purpose of haemodialysis and identify the target group.
7. One product of human cells is nitrogenous wastes. Identify the source of these wastes and the form in
which they are released into the blood.
8. Ammonia is toxic to most living cells. Compare the form which three different animals excrete this
waste product and suggest factors which account for these differences.
9. Osmoregulation is a process used by many fish to maintain an internal balance. Using diagrams
indicate the main features of osmoregulation and outline the situations where it is important to fish.
10. Specific hormones such as ADH and aldosterone help regulate the chemical balance of our body.
State the role of each of these hormones and indicate some situations which may trigger their release.
11. The properties of cohesion (sticking together) and adhesion (sticking to other things) help drive
transpiration in plants. Explain the role of these properties in the continuation of the transpiration
stream through plants.
12. Draw a transverse cross-sectional diagram which shows the location of xylem and phloem vessel
tissue in a typical plant stem.
13. Movement of sugars through phloem involves a loading and unloading process. Describe the structure
of phloem tissue which allows for the loading and unloading of sugars.
14. The movement of water through xylem vessels relies on the properties of cohesion and adhesion of
water molecules. Outline the factors which contribute to the transport of water in the xylem.
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