Describe the role of the nephron in the production of urine.

Cambridge International IGCSE Biology (0610) — 13.1 Excretion in humans · Describe · 4 marks · View as Markdown

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

Model answer (4 marks)

Blood enters the glomerulus where filtration occurs
All glucose is reabsorbed back into the blood in the renal tubule
Most water (and some ions/salts) is reabsorbed back into the blood in the renal tubule
The remaining fluid — containing urea, excess water and excess ions — forms urine

Examiner tips

Use the exact sequence of events: filtration, reabsorption, excretion
Mention the key structures: glomerulus, renal tubule
Keep the answer concise and to the point
Use UK spelling

Common mistakes

Confusing filtration with secretion
Omitting the reabsorption of glucose
Failing to state that urine is the remaining fluid

Mark scheme (4 marks)

Blood enters the glomerulus where filtration occurs
All glucose is reabsorbed back into the blood in the renal tubule
Most water (and some ions/salts) is reabsorbed back into the blood in the renal tubule
The remaining fluid — containing urea, excess water and excess ions — forms urine

Key terms in this question

nephron · urine