Review Problems week 5 (Glycogen, Signal Transduction) don’t forget
problems left over from week 3.
1) How many states of phosphorylase are there? Describe how they are interconverted.
2) What is meant by processivity? Give an example of a processive enzyme.
3) What are the general steps associated with signal transduction.
4) What hormone(s) activate glycogen breakdown in the liver? In muscle?
5) Describe the signal transduction pathway associated with breakdown of muscle
glycogen. Name each participant and assign a role to it.
6) What is meant by reciprocal regulation. Give an example.
7) Describe the processes that give rise to termination of the signal for glycogen
breakdown in muscle.
8) What enzyme activities are required for glycogen synthesis? Describe what these
enzymes do.
9) What hormone activates glycogen synthesis? How does this relate to the physiological
role of the hormone?
10) Describe the receptor that is associated with the hormone in question 9.
11) Many steps in signal transduction involve activation of an enzyme. Give three
examples of such activation. Why is it advantageous to include enzyme activation in a
signal transduction pathway?
12) Name two function activated by insulin that directly affect glucose utilization.
13) How is the insulin signal terminated?
14) Describe the structure of glycogen. Use chemical structures as necessary.
15) What enzyme activities are required for glycogen breakdown? Describe what these
enzymes do.
16) Describe the differences in the biochemistry of glycogen breakdown in the muscle
and liver. How do these differences relate to the physiological functions of muscle and
liver.
17) The synthesis of UDP-glucose requires UTP and glucose-1-phosphate. What would
be the advantages and disadvantages of performing the same reaction using UDP.
18) Phosphorylase uses Pi as a substrate. What is the advantage of this?
19) Write the general mechanisms for the two most common decarboxylation reactions
that utilize TPP.