A receptor site that a molecule can bind to that changes the shape of the active site is called a(n) a) allosteric site
b) active site
c) disulphide bridge
d) MHC receptor

a) allosteric site

Explanation:

An allosteric site is a site on an enzyme other than the active site where a molecule that is not a substrate binds. This changes the shape of the enzyme, making it harder for the substrate to bind and inhibits enzyme activity.

Hope that helps.

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.