AQA GCSE Biology
AQA GCSE Biology 4.5.1 Homeostasis Exam Questions
Free AQA GCSE Biology exam questions for 4.5.1 Homeostasis, with a mark scheme for every pack. Covers the definition of homeostasis, internal conditions controlled, receptors, coordination centres and effectors, and negative feedback in automatic control systems.
4.5.1 Homeostasis exam questions
4 question packs of real past exam questions, each with its mark scheme. Do not stop after a few: answer as many as you can without notes, then mark every answer with the mark scheme. The more questions you do, the more quickly you will spot how examiners ask about each idea.
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About AQA GCSE Biology 4.5.1 Homeostasis
Homeostasis opens the AQA Homeostasis and response topic, examined on Paper 2. It introduces the idea that the body must keep internal conditions within set limits for enzymes and cells to work, and sets out the general pattern of every control system: stimulus, receptor, coordination centre, effector, response. This framework is then applied to the nervous system, hormones, blood glucose, water balance and (Biology only) body temperature. Examiners often ask you to define homeostasis, identify the parts of a control system in an unfamiliar example, and explain why conditions must be controlled.
What you need to know
- Definition Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.
- Why it matters Homeostasis maintains optimal conditions for enzyme action and all cell functions. In the human body it controls blood glucose concentration, body temperature and water levels.
- Automatic control systems Control systems may involve nervous responses or chemical (hormonal) responses. All include receptor cells that detect stimuli, coordination centres (such as the brain, spinal cord and pancreas) that receive and process information, and effectors that bring about responses.
- Effectors Effectors are muscles or glands. Muscles respond by contracting; glands respond by secreting chemicals such as hormones or enzymes.
- Negative feedback When a level moves away from the normal value, the control system brings about a response that returns it towards normal. Examples include insulin and glucagon controlling blood glucose and thyroxine control (Higher tier only).
Common mistakes in 4.5.1 Homeostasis
- Defining homeostasis as 'keeping conditions constant'. Conditions fluctuate within narrow limits around an optimum; homeostasis regulates them in response to change.
- Mixing up receptors and effectors. Receptors detect stimuli; effectors (muscles or glands) carry out the response.
- Saying the coordination centre is always the brain. The spinal cord and pancreas are also coordination centres.
- Forgetting why control matters. Link it to enzymes working at their optimum and cells not being damaged by water loss or gain.
Try three 4.5.1 Homeostasis exam-style questions
1. Define homeostasis. (2 marks)
Show the mark scheme answer
Regulation of internal conditions of a cell or organism; to maintain optimum conditions for function in response to internal and external changes
2. Name three internal conditions controlled by homeostasis in humans. (3 marks)
Show the mark scheme answer
Blood glucose concentration; body temperature; water levels
3. Describe the role of receptors, the coordination centre and effectors in a control system. (3 marks)
Show the mark scheme answer
Receptors detect a stimulus or change; coordination centre receives and processes information from receptors; effectors bring about a response to restore optimum levels
4.5.1 Homeostasis FAQs
What does AQA GCSE Biology 4.5.1 Homeostasis cover?
It covers what homeostasis is, why internal conditions must be controlled, and how automatic control systems use receptors, coordination centres and effectors.
Which paper is 4.5.1 Homeostasis examined on?
Homeostasis and response is assessed on Paper 2.
How can I apply homeostasis to unfamiliar examples?
Identify the stimulus, the receptor, the coordination centre, the effector and the response, then explain how the response returns the condition to its normal level.
