Explain why homeostasis is important for the body to function normally.

Edexcel GCSE Biology (1BI0) — 7.2 Homeostasis · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

A patient with a severe infection develops a very high body temperature and their blood glucose concentration drops well below the normal range. Doctors work to restore both values to normal levels.

Model answer (4 marks)

Homeostasis is the maintenance of a stable internal environment despite fluctuations in internal and external conditions.

Enzymes in the body work best at normal body conditions – temperature, pH and glucose levels – so deviations reduce enzyme activity.

If blood glucose concentration falls too low, cells cannot carry out respiration efficiently and lack energy for metabolic processes.

Restoring normal conditions allows effectors and organs to function correctly and body processes to return to the normal range.

Examiner tips

Use the definition of homeostasis first, then give two specific examples of how deviations affect enzymes and metabolism, and finish with the consequence of restoring normality.
Show the logical sequence: fluctuation → enzyme inefficiency / energy shortage → impaired function → need for restoration.
Use UK spelling and precise terminology (e.g., ‘optimum’, ‘effectors’).

Common mistakes

Confusing homeostasis with homeorhesis or general health; not linking temperature or glucose to enzyme activity; omitting the final point about restoring normal function.

Mark scheme (4 marks)

Homeostasis is the maintenance of a stable internal environment despite fluctuations in internal and external conditions
Enzymes in the body work best / have an optimum at normal body conditions (temperature / pH / glucose levels), so deviations reduce enzyme activity
If blood glucose concentration falls too low, cells cannot carry out respiration efficiently / lack energy for metabolic processes
Restoring normal conditions allows effectors / organs to function correctly and body processes to return to the normal range

Key terms in this question

homeostasis