AQA GCSE Biology 4.3.2 Monoclonal Antibodies Exam Questions

About AQA GCSE Biology 4.3.2 Monoclonal Antibodies

Monoclonal antibodies is a Biology only section of AQA Infection and response and is Higher tier only, examined on Paper 1. It builds on your knowledge of lymphocytes and antibodies from 4.3.1 and explains how identical antibodies, specific to one antigen, are made in the lab and used in medicine and research. Examiners typically ask you to describe how monoclonal antibodies are produced, explain how a pregnancy test works, and evaluate their use in treating cancer, including the fact that they caused more side effects than expected when first trialled.

What you need to know

• What they are Monoclonal antibodies are produced from a single clone of cells. They are specific to one binding site on one protein antigen, so they can target a specific chemical or specific cells in the body (Higher tier only).
• Production Mouse lymphocytes, which make a particular antibody, are combined with a tumour cell to make a hybridoma cell. The hybridoma can both divide and make the antibody. A single hybridoma is cloned to produce many identical cells, and the antibodies are collected and purified.
• Pregnancy tests Pregnancy tests use monoclonal antibodies that bind to the hormone hCG, which is found in the urine of pregnant women. Antibodies on the test strip carry a colour, giving a visible line where hCG is present.
• Diagnosis and research Monoclonal antibodies are used in laboratories to measure levels of hormones and other chemicals in blood, and to detect pathogens. In research they can be bound to a fluorescent dye to locate or identify specific molecules in a cell or tissue.
• Treating cancer Antibodies specific to cancer cells can be bound to a radioactive substance, a toxic drug or a chemical that stops cells growing and dividing. They deliver the substance to the cancer cells without harming other cells in the body as much.
• Advantages and disadvantages They target specific cells, reducing harm to healthy tissue. However, monoclonal antibodies create more side effects than expected and are not yet as widely used as everyone hoped when they were first developed.

Common mistakes in 4.3.2 Monoclonal Antibodies

• Saying the hybridoma is made from two lymphocytes. It is made by fusing a mouse lymphocyte with a tumour (cancer) cell.
• Forgetting why a tumour cell is used. Tumour cells divide rapidly, so the hybridoma can be cloned to make large numbers of antibody-producing cells.
• Saying monoclonal antibodies destroy cancer cells by themselves in every case. They often act by carrying a drug, toxin or radioactive substance to the cancer cells.
• Saying pregnancy tests detect the baby or progesterone. They detect the hormone hCG in urine.

Try three 4.3.2 Monoclonal Antibodies exam-style questions