OCR GCSE Biology A: Monoclonal antibodies, aseptic technique and drug development (J247) – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover OCR GCSE (9-1) Gateway Science Biology A (J247), Version 4.0 (August 2026), statements B6.3m, B6.3n, B6.3p and B6.3q. Questions 1 to 5 test statements printed in bold in the specification, which are Higher Tier only. Questions 6 to 11 are not tier-restricted. Read the study guide and revision notes first. The hub is OCR GCSE Biology, with a checklist and free diagnostics.

Questions

1. (Higher Tier only) Describe how monoclonal antibodies against a chosen antigen are produced. [4]

2. (Higher Tier only) Explain why a B lymphocyte is fused with a tumour cell rather than being used on its own. [3]

3. (Higher Tier only) A pregnancy test strip has mobile antibodies with coloured beads, a test line and a control line.

(a) Name the substance the test detects. [1] (b) Explain how a coloured test line forms in a positive result. [3] (c) A test shows no coloured line at the control line. State what this means. [1]

4. (Higher Tier only) A laboratory measures PSA in the blood of four men using monoclonal antibodies. In this question, levels above 4.0 ng/mL lead to further tests.

Man	A	B	C	D
PSA (ng/mL)	1.4	3.6	5.2	9.8

(a) State which men are offered further tests. [1] (b) Calculate how many times higher man D’s level is than 4.0 ng/mL. [1] (c) Explain why the result alone cannot confirm prostate cancer. [2]

5. (Higher Tier only) Explain how a monoclonal antibody could be used to treat a cancer with fewer side effects than the drug alone. [4]

6. A student prepares to inoculate a nutrient agar plate. State three precautions that prevent contamination of the culture. [3]

7. Explain each of the following in aseptic technique.

(a) Nutrient agar and glassware are autoclaved before use. [2] (b) The lid of the Petri dish is taped in only two or three places. [2]

8. (Calculation) A bacterial colony grows from a diameter of 12 mm to a diameter of 18 mm. Calculate the percentage increase in its area. Give your answer to the nearest whole number. [5]

9. (Calculation) Two antibiotic discs, each of diameter 6 mm, are placed on a plate of bacteria. Antibiotic X gives a clear zone of diameter 18 mm. Antibiotic Y gives a clear zone of diameter 26 mm. Calculate the area of clear agar around each disc (not counting the disc) and state what the results suggest. [5]

10. Put these stages of developing a new medicine in the correct order, and give the main aim of each of the clinical stages: phase 3 trial, preclinical testing, phase 1 trial, phase 2 trial, discovery of a candidate chemical. [4]

11. A company tests an inhaled drug for asthma. 100 patients were given the drug and 100 were given a placebo inhaler. Over 12 weeks, 64 patients on the drug and 38 on the placebo had no asthma attacks. Side effects were reported by 12 patients on the drug and 5 on the placebo.

(a) Calculate the percentage of each group with no attacks, and the gap between them. [3] (b) Explain why a placebo group and double-blind design were used. [2] (c) Evaluate whether the company should apply for approval, using the data. [3]

Answers

1. The antigen is injected into a mouse [1] and B lymphocytes making the antibody are taken from it [1]. These are fused with tumour cells to make hybridoma cells, which are screened to select those making the right antibody [1]. The selected cells are cloned and grown in large numbers, and the antibodies are collected and purified [1]. [4] Examiner insight: A description needs the stages in a logical order; “fuse” without saying what is fused earns less than naming lymphocytes and tumour cells.

2. A lymphocyte makes the specific antibody [1] but does not divide for long, so would give little antibody [1]. The tumour cell divides without limit, so the hybridoma forms a large clone making one antibody [1]. [3] Examiner insight: “Explain” needs the role of each cell stated separately; answers saying the tumour cell makes the antibody lose the first point.

3. (a) hCG [1]. [1] (b) Urine carries mobile antibodies bound to hCG along the strip [1]. Fixed antibodies at the test line bind the hCG [1]. Beads attached to the antibodies collect there and give a coloured line [1]. [3] (c) The test has not worked and should be repeated [1]. [1] Examiner insight: Name the hormone, not just “pregnancy hormone”, and say that the antibodies are held in place at the line.

4. (a) Men C and D [1]. [1] (b) 9.8 ÷ 4.0 = 2.45, so about 2.5 times [1]. [1] (c) Other conditions of the prostate can also raise PSA [1], so a raised level is a reason for further tests, not proof of cancer [1]. [2] Examiner insight: In data questions, quote the value and use the cut-off given in the question rather than a value you remember.

5. Cancer cells have antigens on their surface that few healthy cells have [1]. A monoclonal antibody that binds this antigen is made [1] and attached to the drug [1]. The drug is delivered to the cancer cells, so fewer healthy cells are exposed and there are fewer side effects [1]. [4] Examiner insight: Both the targeting (antigen and antibody) and the benefit (fewer healthy cells harmed) are needed. Do not claim the treatment cures cancer.

6. Any three from the following, one mark each: wipe the bench with alcohol disinfectant; sterilise the loop in a flame until red hot; work close to a Bunsen burner; lift the lid only slightly and briefly; use sterilised (autoclaved) agar and dishes. [1][1][1] [3] Examiner insight: Three different precautions are needed. Repeating “keep it sterile” in different words scores once at most.

7. (a) Steam under pressure heats the items above 100 °C [1], which kills all microorganisms and their spores so none grow in the culture other than the one added [1]. [2] (b) Oxygen can still enter [1], so anaerobic pathogens are less likely to grow [1]. [2] Examiner insight: Each “explain” needs a reason as well as the technique; for taping, “to keep the lid on” alone gives only the obvious half.

8. First r = 12 ÷ 2 = 6 mm [1] and area = π × 6² = 113.1 mm² [1]. Then r = 18 ÷ 2 = 9 mm [1] and area = π × 9² = 254.5 mm² [1]. Increase = (254.5 − 113.1) ÷ 113.1 × 100 = 125% [1]. [5] Examiner insight: Use the radius, not the diameter. Percentage change is divided by the original value, not the new one.

9. Radius of disc = 3 mm [1]. X: π × (9² − 3²) = π × 72 = 226 mm² [1]. Y: π × (13² − 3²) = π × 160 = 503 mm² [1]. Y gives about 2.2 times the area [1]. Y appears more effective against this bacterium, provided both discs held the same amount of antibiotic and the plates were treated the same [1]. [5] Examiner insight: A fair comparison needs the conditions kept equal. Say what must be controlled before drawing the conclusion.

10. Order: discovery of a candidate chemical, preclinical testing [1], phase 1, phase 2, phase 3 [1]. Phase 1 aims to test safety (healthy volunteers) [1]. Phase 3 aims to confirm that it works and is safe in many patients compared with a placebo or existing treatment [1]. [4] Examiner insight: Two aims are asked for. Writing “check if it works” for phase 1 is a common slip because phase 1 is mainly about safety.

11. (a) Drug: 64 ÷ 100 × 100 = 64% [1]. Placebo: 38% [1]. Difference = 26 percentage points [1]. [3] (b) The placebo group shows how many improve without the drug, through expectation or natural change [1]. Double-blind means neither patients nor doctors know who has the drug, so they cannot bias the results [1]. [2] (c) More were attack-free on the drug (64% against 38%), a difference of 26 points [1]. Side effects were more common on the drug (12% against 5%), but this was still a small proportion [1]. Reasonable to apply for approval, as the benefit appears greater than the risk, though further monitoring is needed and a larger sample would reduce the effect of chance [1]. [3] Examiner insight: An evaluation needs figures from both benefit and harm, followed by a judgement. A conclusion with no data from the table is not enough.

Where marks are usually lost

• Writing that the tumour cell makes the antibody, or that the hybridoma is “a monoclonal antibody”.
• Naming “a pregnancy hormone” instead of hCG, and forgetting what the control line shows.
• Describing monoclonal antibody cancer treatment as a proven cure.
• Giving three aseptic precautions that are really one idea, such as “keep it clean”.
• Leaving out why a technique works, for example not saying that autoclaving also kills spores.
• Using the diameter in πr², or forgetting to subtract the disc when asked for clear agar.
• Dividing by the new value rather than the original when finding percentage change.
• Treating phase 1 as a test of effectiveness.
• Judging a trial from the drug group alone, without comparing with the placebo group.

Next steps

• Re-read the revision notes and the study guide.
• Open the OCR GCSE Biology hub and tick off statements on the checklist.
• Try all the free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

OCR GCSE (9-1) Gateway Science Biology A (J247), Version 4.0 (August 2026), for first assessment in 2018, published by OCR. Statements B6.3m, B6.3n, B6.3p and B6.3q.