Exam 3: Labs

Question 1

Describe what ELISA testing is used for. Give a general description of how the test is done.

Answer 1

• used to detect and quantify substances such as proteins, antibodies, hormones, or antigens
• uses antibodies that specifically bind to the target molecule (antigen) and an enzyme-conjugated secondary antibody
• enzyme generates a detectable signal, usually a color change, upon interaction with its substrate

Question 2

Describe what SDS-PAGE testing is used for. Give a general description of how the test is done.

Answer 2

• used to separate proteins based on their molecular weight
• proteins are denatured and coated with the negatively-charged detergent SDS, which masks their native charge
• proteins are separated in a polyacrylamide gel under an electric field (smaller proteins migrating faster through the gel matrix)

Question 3

Describe what Western blot testing is used for. Give a general description of how the test is done.

Answer 3

• used to detect specific proteins in a sample using antibodies
• proteins are separated by SDS-PAGE, transferred onto a membrane, and probed with antibodies for specific detection