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12 exam-style questions with model answers, plus 16 quick multi-choice questions — every question on the site for this standard, grouped by the 4 pages of notes they come from.
Write a full answer before you reveal the model one — that comparison is where the marks come from. Every block links back to the notes that teach it.
Describe what is meant by homeostasis, and describe the components of a homeostatic control system.
Explain how negative feedback maintains a stable internal environment, and explain why most control systems have two opposing sets of effectors.
Homeostasis is metabolically expensive. Discuss its adaptive advantage, and evaluate why some animals invest heavily in it while others do not.
Describe the responses that occur when an animal becomes too cold, and describe the components of the osmoregulation control system.
Explain how the body responds when blood water potential falls after heavy sweating, and explain why this response is described as negative feedback.
Thermoregulation and osmoregulation can make conflicting demands on the body. Discuss this conflict, and evaluate how the body resolves it and what happens when it cannot.
Describe how blood glucose concentration is returned to the set point after it rises, and describe the components of the blood pressure control system.
Explain how blood glucose is maintained during prolonged exercise without eating, and explain why insulin and glucagon are described as antagonistic.
Compare the blood glucose and blood pressure control systems, and evaluate why each uses the signalling method it does.
Describe how the body responds to a rise in blood carbon dioxide, and describe two ways a control system can break down.
Explain why ventilation is controlled mainly by carbon dioxide rather than by oxygen, and explain how the carbonic acid equilibrium makes CO2 detectable.
Analyse how the breakdown of a control system differs from that system simply ceasing to work, using hypothermia and diabetes as examples.