Practise 45 exam-style questions on Uses of monoclonal antibodies (biology only) for AQA GCSE Biology. Write your answer as you would in the exam and get it marked in seconds against the mark scheme, point by point, with an AI tutor on hand if you get stuck.
45 questions
3–6 marks each
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20 questions, marked as you go
Sample questions with model answers
Here are 4 of the questions in this topic, each with a model answer, an explanation of why it earns the marks and the mark scheme an examiner would use.
Question 1
3 marks
Why are monoclonal antibodies useful in cancer diagnosis (immunohistochemistry) compared with general stains?
Model answer
Monoclonal antibodies bind specific tumour markers allowing identification of cell type, origin and malignant vs benign; they provide molecular specificity not possible with general histological stains and can detect low-level antigen expression.
Explanation
Immunohistochemistry uses antibodies to detect antigens uniquely or preferentially expressed by certain tumours, enabling specific diagnostic and prognostic information beyond morphology alone.
Mark scheme
1 mark
Bind specific tumour markers (molecular specificity)
1 mark
Allow identification of cell type/origin and diagnosis subtype
1 mark
More sensitive/specific than general stains and can detect low expression
Question 2
4 marks
Explain how monoclonal antibodies can be used to locate a specific protein inside cells using fluorescence.
Model answer
Monoclonal antibodies specific to the protein are chemically linked to a fluorescent dye. The antibodies penetrate/t bind to the target protein in fixed/permeabilised cells. When illuminated with the appropriate wavelength, the dye fluoresces, revealing the protein’s location under a fluorescence microscope.
Explanation
By attaching a fluorescent label to a monoclonal antibody, researchers can use the antibody’s specificity to bind only the protein of interest and then detect its position in cells or tissues by fluorescence microscopy.
Mark scheme
1 mark
Monoclonal antibodies specific to the target protein are labelled with a fluorescent dye
1 mark
Antibodies bind to the protein in (fixed) cells or tissue (permeabilised if intracellular)
1 mark
Illumination with the correct wavelength causes the dye to fluoresce
1 mark
Fluorescence observed with microscope shows the protein’s location
Question 3
4 marks
Explain how multiplexed monoclonal antibody assays work and provide one application where multiplexing is advantageous.
Model answer
Different monoclonal antibodies, each with a distinct label (different fluorophores or bead IDs), detect multiple analytes simultaneously in one sample. Advantageous for profiling cytokines in immune monitoring or running panels of infectious disease markers where sample volume or time is limited.
Explanation
Multiplexing increases throughput and provides a comprehensive panel from limited samples, useful in clinical and research settings.
Mark scheme
1 mark
Multiple monoclonal antibodies each labelled distinctly detect several analytes in same sample
In antibody therapy, explain the terms 'humanised' and 'fully human' antibody and why humanisation reduces immunogenicity compared with murine antibodies.
Model answer
Humanised antibodies replace most mouse antibody regions with human sequences except the antigen-binding CDRs; fully human antibodies are entirely human sequences. Humanisation reduces foreign (murine) protein content, lowering immune recognition and anti-drug antibody formation compared with murine antibodies which are highly immunogenic.
Explanation
Reducing non-human sequences in therapeutic antibodies reduces the probability that the patient's immune system will mount neutralising or hypersensitivity responses, improving tolerability.
Mark scheme
1 mark
Humanised = mouse CDRs grafted onto human antibody framework/constant regions
1 mark
Fully human = antibody sequence entirely human (from human libraries/transgenic animals)
1 mark
Murine antibodies are non-human and evoke immune responses (higher immunogenicity)
1 mark
Humanisation reduces murine content so less likely to be recognised as foreign
1 mark
Reduced anti-drug antibody formation improves safety and therapeutic efficacy
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