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IGCSEBiology
Trial Class

Original practice · 5 questions · 15 marks · about 17 minutes

Kidney Structure and Function Practice Questions

Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.

These questions test your understanding of how the kidneys filter blood, remove waste, and regulate water balance.

Before you open the answers

  • Attempt every question without notes.
  • Show working for calculations and write complete biological statements.
  • Use the suggested time as a guide, not a strict limit on the first attempt.

These are original practice questions. They do not reproduce an official Cambridge paper or official mark scheme.

  1. Question 1

    Paper 4 Extended 4 marks Difficulty 4/5

    Describe the processes of ultrafiltration and selective reabsorption in the nephron.

    Show model answer and marking guidance
    1. Ultrafiltration: blood is filtered in the glomerulus under high pressure.
    2. Small molecules (water, glucose, urea, ions) pass into the Bowman's capsule; large molecules (proteins, blood cells) remain in the blood.
    3. Selective reabsorption: useful substances (all glucose, most water, some ions) are reabsorbed in the proximal convoluted tubule.
    4. Reabsorption of glucose occurs by active transport; water by osmosis.

  2. Question 2

    Paper 4 Both 3 marks Difficulty 3/5

    Name three substances found in the filtrate in the Bowman's capsule and one substance that is not filtered.

    Show model answer and marking guidance
    1. Filtered: water, glucose, urea (also ions / amino acids).
    2. Not filtered: proteins (too large to pass through the capillary wall).
    3. Blood cells are also too large to be filtered.

  3. Question 3

    Paper 4 Extended 3 marks Difficulty 3/5

    Explain why all glucose is reabsorbed from the filtrate but urea is not.

    Show model answer and marking guidance
    1. Glucose is useful: needed for respiration to release energy.
    2. Glucose is selectively reabsorbed by active transport in the proximal tubule.
    3. Urea is a toxic waste product of protein metabolism: it must be excreted, so it remains in the filtrate.

  4. Question 4

    Paper 2 Core 2 marks Difficulty 1/5

    Name the two main waste products removed by the kidneys.

    Show model answer and marking guidance
    1. Urea (from the breakdown of excess amino acids in the liver).
    2. Excess water and ions / salts.

  5. Question 5

    Paper 4 Extended 3 marks Difficulty 4/5

    A person with kidney disease has protein in their urine. Explain what this suggests about their kidneys.

    Show model answer and marking guidance
    1. Normally proteins are too large to pass through the filter in the glomerulus.
    2. Protein in urine suggests the glomerular capillaries or Bowman's capsule are damaged.
    3. The filtration membrane has become more permeable: allowing proteins to leak through.

Mark the set consistently

Award a point only when the idea is clearly present in the written answer. Correct any missed point in a complete sentence, then test the same skill on a different question several days later.

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