22. Carbohydrate Metabolism

The following metabolites are present both in glycolysis and gluconeogenesis, except:

Which molecule is added to pyruvate and then removed in the next reaction?

Enzyme responsible for decarboxylation and phosphate transfer in the same gluconeogenic reaction is:

Fructose-1,6-bisphosphate is dephosphorylated by ________________ to fructose-6-phosphate.

Which of the following statement(s) correctly describes the Cori cycle?

What is the purpose of the Cori cycle?

Outline the conditions that direct pyruvate toward the following:

d. Glucose synthesis (gluconeogenesis)

In what tissues or organisms is each pathway present?

How many steps in gluconeogenesis are not the exact reversal of the steps in glycolysis? What kind of conversion of substrate to product does each involve? What is the common theme in each of these reactions?

Explain why the Cori cycle is necessary and when your cells would use this cycle.

Lactate can be converted into pyruvate by the enzyme lactate dehydrogenase and the coenzyme NAD⁺. Write the reaction in the standard biochemical format, using a curved arrow to show the involvement of NAD⁺.

Why is it important for muscle cells to export lactate into the bloodstream during heavy exercise?

Name the anabolic pathway for making glucose.

Name the two molecules that serve as starting materials for glucose synthesis.

Why does glycogenolysis use fewer steps than the reverse process, glycogenesis? Which process uses less energy?

Indicate whether the statements below apply to the glucose-regulating hormone insulin or to glucagon:

(a) signals cells to take up glucose