GLUCONEOGENESIS, THE PENTOSE PHOSPHATE PATHWAY, and GLYCOGEN METABOLISM
1. Which amino acids can be used in gluconeogenesis?
A. Leucine
B. Lysine
C. Glycine
D. Valine
E. Serine
2. Where does gluconeogenesis occur?
A. Liver
B. Spleen
C. Small intestine
D. Kidney
E. Stomach
3. What is the only thing you cannot make glucose from?
A. Amino acids
B. Fatty acids
C. Glycerol
D. Lactic acid
E. Pyruvic acid
4. What are the substrates for gluconeogenesis in times of prolonged fasting?
A. Lactate
B. Pyruvate
C. Glycerol
D. Alpha-ketoacids
E. Glycogen
5. Name the unique enzymes of gluconeogenesis:
A. Pyruvate kinase
B. Pyruvate dehydrogenase
C. Pyruvate carboxylase
D. Glucokinase
E. Hexokinase
6. Name the unique enzymes of gluconeogenesis:
A. Glucose 6-phosphatase
B. Phosphoglucose isomerase
C. Phosphoglucomutase
D. Fructose 1,6-bisphosphatase
E. Phosphoglycerate mutase
7. What is the role of pyruvate carboxylase?
A. Pyruvate → lactate
B. Pyruvate → acetyl-CoA
C. Pyruvate → alanine
D. Pyruvate → oxaloacetate
8. Where does pyruvate carboxylase work?
A. In cytosol
B. In mitochondrial matrix
C. In endoplasmic reticulum
D. In nucleus
E. In the blood
9. What is the coenzyme used by pyruvate carboxylase?
A. Biotin
B. Pyridoxal phosphate
C. Thiamine diphosphate
D. Tetrahydrofolate
E. Ascorbic acid
10. What is the role of PEP carboxykinase?
A. PEP → pyruvate
B. PEP → oxaloacetate
C. 2-phosphoglycerate → PEP
D. Pyruvate → lactate
E. Pyruvate → oxaloacetate
11. What is used to decarboxylate cytosolic oxaloacetate?
A. Carbon dioxide
B. Water
C. GTP
D. ATP
E. NADH
12. What is the expensive reaction in gluconeogenesis that generates a very high energy intermediate?
A. Pyruvate carboxylase
B. PEP carboxykinase
C. Enolase
D. Glyceraldehyde 3-phosphate dehydrogenase
E. Lactate dehydrogenase
13. What is the hydrolytic enzyme that overcomes the second irreversible step in gluconeogenesis?
A. Pyruvate dehydrogenase
B. Pyruvate carboxylase
C. PEP carboxykinase
D. Fructose 1,6-bisphosphatase
E. Glucose 6-phosphatase
14. What overcomes the last irreversible step in gluconeogenesis?
A. Pyruvate dehydrogenase
B. Pyruvate carboxylase
C. PEP carboxykinase
D. Fructose 1,6-bisphosphatase
E. Glucose 6-phosphatase
15. What is the energy requirement for gluconeogenesis (starting with two pyruvate molecules)?
A. 2 ATP
B. 4 ATP
C. 6 ATP
D. 8 ATP
E. 10 ATP
F.
16. Which one of the following statements concerning GNG is correct:
A. It occurs in muscle
B. It uses carbon skeletons provided by degradation of fatty acids
C. It occurs exclusively in cytosol
D. It is important in maintaining blood glucose during the normal overnight fast
E. It involves lactate as intermediate
17. Which of the following reactions is unique to GNG?
A. Lactate → pyruvate
B. Oxaloacetate → PEP
C. PEP → pyruvate
D. Glucose 6-phosphate → fructose 6-phosphate
E. Fructose 6-phosphate → fructose 1,6-bisphosphate
18. In the glycogen synthase reaction, the precursor to glycogen is:
A. glucose 6-phosphate
B. UTP-glucose
C. UDP-glucose
D. GDP-glucose
E. Glucose 1-phosphate
19. Glycogen has
A. α-1,4 linkages
B. α-1,6 linkages
C. α-1,4 and α-1,6 linkages
D. α-1,4 and β-1,6 linkages
20. What are the two glycogen storage sites in the body?
A. Brain
B. Spleen
C. Small intestine
D. Kidney
E. Liver
F. Skeletal muscles
21. What are the primary products of the pentose phosphate pathway?
A. Glucose 6-phosphate
B. Ribose 5-phosphate
C. NADPH·H+
D. Glyceraldehyde 3-phosphate
E. 6-phosphogluconate
22. Where is the pentose phosphate pathway active in your body?
A. Liver
B. Kidney
C. Adipose tissue
D. Erythrocytes
E. Brain
23. Name the key enzymes of the pentose phosphate pathway:
A. Glucose 6-phosphatase
B. Glucose 6-phosphate dehydrogenase
C. Lactonase
D. 6-phosphogluconate dehydrogenase
E. Glucokinase
24. What can be synthesized with the use of NADPH?
A. Glucose
B. Fatty acids
C. Amino acids
D. Cholesterol
E. Steroid hormones
25. Which vitamin is synthesized with the use of NADPH?
A. A
B. E
C. D
D. K
E. H
26. Indicate which statements about the pentose phosphate pathway are true:
A. It generates NADH for reductive biosynthesis
B. The reactions occur in the cytosol
C. It is more active in myocytes than in adipocytes
D. It interconverts trioses, tetroses, pentoses, hexoses, and heptoses
E. Through this pathway, excess ribose 5-phosphate can be converted into glycolytic intermediates
27. Indicate which statements about the pentose phosphate pathway are false:
A. It generates NADPH for reductive biosynthesis
B. The reactions occur in the cytosol
C. The reactions occur in the mitochondria
D. It is more active in myocytes than in adipocytes
E. It interconverts trioses, tetroses, pentoses, hexoses, and heptoses
28. Indicate which statements about gluconeogenesis are true:
A. It occurs completely in the mitochondrial matrix
B. Pyruvate carboxylase, catalyzing an anaplerotic reaction, is the first regulatory enzyme in the pathway
C. Precursors of hexoses include lactate, pyruvate, glycerol, and alanine
D. The three bypass reactions have ΔG values near zero, whereas other gluconeogenic reactions have large, negative ΔG values
E. Some reactions occur in the mitochondrial matrix and some in the cytoplasm
29. Name the initial product of phosphorolysis of glycogen by phosphorylase:
A. Glucose 1-phosphate
B. Glucose
C. Glucose 6-phosphate
D. Fructose 1-phosphate
E. Fructose
30. Indicate the class of glucose 6-phosphatase:
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Isomerase
F. Ligase