A scientist is developing a test to detect a bacterial infection in blood samples. She attaches a fluorescent dye to monoclonal antibodies specific to bacterial surface antigens. What is the purpose of attaching the fluorescent dye?

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Question

A scientist is developing a test to detect a bacterial infection in blood samples. She attaches a fluorescent dye to monoclonal antibodies specific to bacterial surface antigens. What is the purpose of attaching the fluorescent dye?

Accepted Answer

B. To allow detection of the antibody–antigen complex under a fluorescence microscope — The fluorescent dye is a label attached to the antibody so that when the antibody binds to its specific antigen on the bacteria, the complex can be visualised using a fluorescence microscope. The dye does not affect binding strength, does not increase bacterial numbers, and does not destroy bacteria — it is purely a detection tool.

Answer

D. To destroy the bacteria once the antibody has bound

Answer

B. To allow detection of the antibody–antigen complex under a fluorescence microscope

Answer

C. To increase the number of bacteria present in the sample

Answer

A. To make the antibodies bind more strongly to the bacteria

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