The functions of some proteins change depending on whether they are in the light or in the dark they are photoreceptive (PR) proteins. A team of scientists recently determined that PR proteins bind to DNA to regulate gene expression in microbes. Answer the following three questions about this scenario.
-A single PR protein is composed of four identical polypeptide chains that act together to bind DNA. What is the highest level of protein structure that the PR proteins have?
A) primary
B) secondary
C) tertiary
D) quaternary

Question

Quizplus · Accepted Answer

The fact that a PR protein is composed of four identical chains that act together indicates that it has quaternary structure, which is the highest level of protein structure.

The Functions of Some Proteins Change Depending on Whether They