Exam Connection

🎯 Exam Connection

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Frequency: Homeostasis Introduction concepts underpin 3 out of 5 recent AQA Paper 2 sittings. The negative feedback model and three-component control system are essential scaffolding for blood glucose (16 marks across 3 papers) and temperature regulation (10 marks across 2 papers).

Edexcel (1BI0/2): Homeostasis principles are examined on Edexcel Paper 2 (1BI0/2) as the foundation for all of Topic 7. Edexcel questions on this topic often provide a graph of a body condition (e.g. blood temperature or glucose) over time and ask students to explain how the body detected the change and restored the set point. The three-component model (receptor, coordination centre, effector) and the phrase "opposes the change" are required for full marks on negative feedback questions across all boards.

Typical question patterns and mark allocations:

• "Define homeostasis" (1 mark) — mark schemes require specific wording: regulation of internal conditions to maintain optimum conditions for function. Learn this exact phrasing.
• "Describe the roles of receptors, coordination centres, and effectors in a control system" (3 marks, 1 per component) — name and describe each part clearly.
• "Explain what is meant by negative feedback" (2 marks) — must state that the response opposes and reverses the original change.
• "Explain, using an example, how negative feedback maintains a stable internal environment" (6 marks, extended response) — requires: stimulus → receptor → coordination centre → effector → corrective response → return to normal, with a named example (temperature or blood glucose).
• "Compare the nervous system and the endocrine system as methods of communication" (4 marks) — requires speed, duration, target specificity, and signal type for each.

Past paper command words for this topic:

• Define — give the precise AQA definition, no more, no less
• Describe — state what happens at each step in the correct order
• Explain — link mechanism to outcome with causal language ("this means that...", "because...")
• Compare — give both similarities AND differences between the two systems