Monoclonal antibodies and ELISAAQA A-Level Biology: Flashcards

What these 12 flashcards ask

What are monoclonal antibodies?
Why is a monoclonal antibody specific to one antigen?
How can monoclonal antibodies target a drug to cancer cells?
Why does targeting reduce side effects?
How does a pregnancy test use monoclonal antibodies?
What is the function of the control line in a pregnancy test?
What does ELISA stand for?
Outline the steps of an ELISA test.
Why is the well washed between ELISA steps?
What does the enzyme do in ELISA?
State two ethical issues with monoclonal antibodies.
Name two ways to evaluate a clinical trial of an antibody drug.

Exam questions on Monoclonal antibodies and ELISA

A hospital is trialling a treatment for a type of breast cancer. A cancer drug is attached to a monoclonal antibody. The antibody binds to a receptor protein that is present in very large numbers on the surface of the tumour cells and in very small numbers on healthy cells.
Explain why the antibody binds to the tumour cells but not to most healthy cells.2 marks
A diagnostic laboratory uses an ELISA test to detect a viral antigen in blood samples. The wells of a plastic plate are coated with the patient's sample so that any antigen sticks to the plastic. A first antibody specific to the viral antigen is then added, followed by a second antibody that carries an enzyme and binds to the first antibody. A colourless substrate is added last.
A technician forgets to wash the well after adding the second antibody. Explain the effect on the result for a well that contains no viral antigen.2 marks
A home pregnancy test detects the hormone hCG in urine. The urine is applied to a pad that contains mobile monoclonal antibodies to hCG attached to blue beads. The liquid flows along a strip past a test line of immobilised monoclonal antibodies to hCG, and then past a control line of immobilised antibodies that bind the mobile antibodies.
Explain how a blue test line appears when the urine contains hCG.3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).