Chapter 22

(Integrates with Chapter 3 .) Suggest an explanation for the exergonic nature of the glycogen synthase reaction \(\left(\Delta G^{\circ \prime}=-13.3 \mathrm{kJ} / \mathrm{mol}\right)\) Consult Chapter 3 to review the energetics of high-energy phosphate compounds if necessary.

(Integrates with Chapter \(7 .)\) Imagine a glycogen molecule with 8000 glucose residues. If branches occur every eight residues, how many reducing ends does the molecule have? If branches occur every 12 residues, how many reducing ends does it have? How many nonreducing ends does it have in each of these cases?

Explain the effects of each of the following on the rates of gluconeogenesis and glycogen metabolism: a. Increasing the concentration of tissue fructose- 1,6 -bisphosphate b. Increasing the concentration of blood glucose c. Increasing the concentration of blood insulin d. Increasing the amount of blood glucagon e. Decreasing levels of tissue ATP f. Increasing the concentration of tissue AMP g. Decreasing the concentration of fructose- 6 -phosphate

Glycogenin catalyzes the first reaction in the synthesis of a glycogen particle, with \(\mathrm{Tyr}^{194}\) of glycogenin (page 676) combining with a glucose unit (provided by UDP-glucose) to produce a tyrosyl glucose. Write a mechanism to show how this reaction could occur.

(Integrates with Chapters 3 and \(14 .\) ) What is the structure of creatine phosphate? Write reactions to indicate how it stores and provides energy for exercise.