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Problem 22.1
Name the following pathways:
c. Pathway for synthesis of glucose from lactate
Problem 22.11
Pyruvate has three different fates. What are the three different molecules pyruvate is converted into? What conditions exist for the formation of each product?
Problem 22.12
Glycolysis of one molecule of glucose produces 8 ATP molecules. How many ATP molecules are produced from glycolysis of 10 glucose molecules?
Problem 22.19
What two types of reactions convert glycerol to dihydroxyacetone phosphate? <IMAGE>
Problem 22.2
What is the purpose of the Cori cycle?
Problem 22.23
Glucose 6-phosphate is in a pivotal position in metabolism. Depending on conditions, glucose 6-phosphate follows one of several pathways. Under what conditions do the following occur?
d. Glycogenesis
Problem 22.23
Glucose 6-phosphate is in a pivotal position in metabolism. Depending on conditions, glucose 6-phosphate follows one of several pathways. Under what conditions do the following occur?
b. Hydrolysis to free glucose
Problem 22.25
Outline the conditions that direct pyruvate toward the following:
d. Glucose synthesis (gluconeogenesis)
In what tissues or organisms is each pathway present?
Problem 22.28
Name the molecules used for gluconeogenesis. What are the sources of these molecules? Under what conditions would gluconeogenesis occur?
Problem 22.29
Fatty acids from stored triacylglycerols (fat) are not available for gluconeogenesis. Speculate why we do not have the enzymes to directly convert fatty acids into glucose. Plants (especially seeds) do have enzymes to convert fatty acids into carbohydrates. Why are they so lucky?
Problem 22.33
What are the major monosaccharide products produced by digestion of carbohydrates?
Problem 22.4
Identify each step in glycolysis that is an isomerization.
Problem 22.42
Which cells, liver, muscle, or brain, use the following pathways?
b. Gluconeogenesis
Problem 22.47
How many moles of ATP are produced by phosphorylation in the following?
a. Glycolysis of 1 mol of glucose
Problem 22.47
How many moles of ATP are produced by phosphorylation in the following?
b. Aerobic conversion of 1 mol of pyruvate to 1 mol of acetyl-CoA
Problem 22.47
How many moles of ATP are produced by phosphorylation in the following?
c. Catabolism of 1 mol of acetyl-CoA in the citric acid cycle
Problem 22.5
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⁺.
Problem 22.54
Differentiate between blood sugar levels and resulting symptoms in hyperglycemia and hypoglycemia.
Problem 22.6
In Figure 22.3, compare the starting compound (glucose) and the final product (pyruvate).
a. Which is oxidized to a greater extent?
Problem 22.6
Why does glycogenolysis use fewer steps than the reverse process, glycogenesis? Which process uses less energy?
Problem 22.61
Name the anabolic pathway for making glucose.
Problem 22.62
Name the two molecules that serve as starting materials for glucose synthesis.
Problem 22.66
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?
Problem 22.68
Explain why the Cori cycle is necessary and when your cells would use this cycle.
Problem 22.7
Use curved arrows (like those in Figure 22.3) to write an equation for the conversion of fructose to fructose 6-phosphate by ATP. At what step does fructose 6-phosphate enter glycolysis?
Problem 22.73
How many moles of ATP are generated from the catabolism of fructose (by glycolysis) in
(a) liver cells?
Problem 22.73
How many moles of ATP are generated from the catabolism of fructose (by glycolysis) in
(b) muscle cells?
Problem 22.75
Why is it important for muscle cells to export lactate into the bloodstream during heavy exercise?
Problem 22.78
What are the characteristics of Type I diabetes?
Problem 22.79
What are the characteristics of Type II diabetes?
