Question

Which of the following types of regulation is considered the major way liver cells activate glycogen phosphorylase?

a. Gene expression
b. Post translational modification
c. Compartmentalization
d. Allosteric regulators

Answer 1

Liver cells primarily activate glycogen phosphorylase through post-translational modification, which is the phosphorylation of the enzyme enabling it to break down glycogen rapidly in response to metabolic needs.

Step-by-step explanation:

The major way liver cells activate glycogen phosphorylase is through post-translational modification. This process involves the modification of proteins after they have been synthesized. In the case of glycogen phosphorylase, this modification is typically the addition of a phosphate group, a process known as phosphorylation, which is catalyzed by phosphorylase kinase in step 6.

Once phosphorylated, glycogen phosphorylase becomes active and can perform its function of breaking down glycogen into glucose-1-phosphate. This regulatory mechanism allows for a rapid response to metabolic demands, such as during the fight-or-flight response, where activated glycogen phosphorylase quickly provides energy for the body.