Monoclonal Antibodies
Get to grips with Monoclonal Antibodies for GCSE Biology with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. A separate (triple) biology topic on how monoclonal antibodies are produced from hybridoma cells and used in pregnancy tests and to treat cancer.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Monoclonal antibodies are identical antibodies produced from a single clone of cells, so they bind to one specific chemical only. This is a Triple-only topic.
They are made by stimulating mouse lymphocytes to produce an antibody against a chosen antigen. The lymphocytes are then combined with a type of tumour cell to make a hybridoma cell, which can both divide rapidly and produce the antibody. Cloning a single hybridoma gives large quantities of identical antibodies.
Uses include pregnancy tests, measuring hormone levels, identifying specific molecules in research, and treating diseases such as cancer by delivering a drug directly to the cancer cells. Their specificity is what makes them useful, but they have caused more side effects than expected.
Revision notes
How they are made
A mouse lymphocyte is stimulated to make an antibody against a particular antigen.
It is combined with a tumour cell to form a hybridoma, which divides rapidly and produces the antibody. A single hybridoma is then cloned to produce large quantities of identical antibodies.
Why specificity matters
Because they are all identical, monoclonal antibodies bind to one specific chemical only.
That allows them to target a particular molecule or cell type in a mixture, which is the basis of every one of their applications.
Uses
Pregnancy tests detect a hormone in urine. In laboratories they measure hormone levels or detect pathogens.
In research they bind to specific molecules with a fluorescent dye. In treatment they can carry a toxic drug or radioactive substance directly to cancer cells without harming normal cells.
Key points
- Monoclonal antibodies come from a single clone of cells.
- They bind to one specific chemical only.
- Lymphocytes are combined with tumour cells to form hybridomas.
- Hybridomas divide rapidly and produce the antibody.
- Uses include pregnancy tests and cancer treatment.
- They have caused more side effects than expected.
Worked examples
Example 1
Explain why monoclonal antibodies are able to target one specific type of cell. [2 marks]
Model answer
They are all identical because they are produced from a single clone of cells (1 mark), so they bind only to one specific antigen found on that cell type (1 mark).
Example 2
Describe how monoclonal antibodies can be used to treat cancer. [3 marks]
Model answer
The antibody is made so that it binds to an antigen found only on cancer cells (1 mark). A toxic drug or radioactive substance is attached to the antibody (1 mark), so it is delivered directly to the cancer cells without harming normal body cells (1 mark).
Example 3
Explain why a hybridoma cell is used rather than a lymphocyte alone. [2 marks]
Model answer
Lymphocytes produce the antibody but do not divide readily (1 mark). Fusing them with tumour cells produces hybridomas that divide rapidly, so large quantities of the antibody can be made (1 mark).
Common mistakes
Saying monoclonal antibodies are made only from tumour cells.
They come from a hybridoma — a lymphocyte fused with a tumour cell.
Forgetting the specificity.
Binding to one specific antigen is the whole reason they are useful.
Saying they have no drawbacks.
They have caused more side effects than expected, which limits their use.
Confusing them with ordinary antibodies.
Monoclonal antibodies are identical and produced artificially from one clone.
Exam tips
- Learn the production sequence: lymphocyte, hybridoma, clone, collect.
- Emphasise specificity when explaining any use.
- Give a drawback if asked to evaluate.
- Remember this is a Triple-only topic.
Key terms
- Monoclonal antibody
- An identical antibody produced from a single clone of cells.
- Hybridoma
- A cell formed by fusing a lymphocyte with a tumour cell.
- Antigen
- A molecule recognised by an antibody.
- Lymphocyte
- A white blood cell that produces antibodies.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.