An enzyme-linked immunosorbent assay (ELISA) is typically performed to detect the presence and/or amount of a target
Question:
An enzyme-linked immunosorbent assay (ELISA) is typically performed to detect the presence and/or amount of a target protein of interest within an experimental sample. Detection of the target protein is made possible by antibodies, which make the ELISA an immunoassay. Through a series of incubation and washing steps, these antibodies, which are frequently linked, or conjugated, to an enzyme, will detect protein coating the bottom of a well on a microtiter plate. When exposed to a substrate, antibody-bound enzyme will cause a color change, thereby indicating the presence of the protein of interest in the sample.
In this video, the theory behind how ELISAs work is explained, including a discussion of both primary and secondary antibody binding and the importance of blocking steps. Theory is followed by practice, as the video progresses to an explanation of the step-by-step procedure. Finally, variations of the standard ELISA such as the sandwich and competitive ELISAs are introduced, and real-world applications of this method, such as in over-the-counter pregnancy tests are explained.
1. For which of the following applications could an ELISA be used?
- To neutralize trypsin within a sample.
- To determine the size of a plasmid within a sample.
- To determine the presence or absence of contamination within a sample.
- To determine the presence or absence of a specific protein within a sample.
2. The target protein is recognized by...
- ...the substrate.
- ...buffer enzymes.
-...unlabeled viral particles.
-...the primary antibody.
3. The absorbance measured for each well is _____to the amount of target protein present in each sample. (cell culture media harvested from human anti-body-producing cell lines).
- equal
- not directly related
- inversely proportional
- directly proportional