Multiple Choice
In an Indirect ELISA, the enzyme-linked antibody will attach to:
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8. Protein Function
ELISA
Multiple Choice
In an indirect ELISA, why is the secondary antibody typically conjugated to an enzyme (e.g., horseradish peroxidase or alkaline phosphatase)?
A
To immobilize the antigen on the microtiter plate surface via covalent attachment
B
To generate a measurable signal by converting an added substrate into a detectable product, enabling amplification of antigen detection
C
To increase the affinity and specificity of antigen binding by directly recognizing multiple epitopes on the antigen
D
To prevent non-specific binding by blocking unoccupied sites on the plate
Verified step by step guidance1
Understand the purpose of the secondary antibody in an indirect ELISA: it binds to the primary antibody that is already attached to the antigen on the plate.
Recognize that the secondary antibody is conjugated to an enzyme such as horseradish peroxidase or alkaline phosphatase to enable a biochemical reaction.
Know that the enzyme linked to the secondary antibody catalyzes the conversion of a colorless substrate into a colored or fluorescent product, which can be measured.
Realize that this enzymatic reaction amplifies the signal because one enzyme molecule can convert many substrate molecules, increasing detection sensitivity.
Conclude that the enzyme conjugation is not for immobilizing antigen, increasing binding affinity, or blocking non-specific sites, but specifically to generate a measurable and amplified signal.
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