1. NADH (nicotinamide adenine dinucleotide)
a. is the energy currency of the cell
b. is required for some oxidation-reduction reactions
c. serves as a high-energy phosphate acceptor
d. is produced during the conversion of pyruvate to lactate
2. The hydrolysis of ATP to ADP + Pi
a. requires coupling to a highly favorable reaction
b. has a positive ΔG
c. involves NAD+
d. releases energy by breaking a high-energy bond
3. Oxidation of fats releases more energy than oxidation of carbohydrates because
a. the carbon atoms in carbohydrates are partially oxidized to start with
b. there are more oxygen atoms per molecule of fat than in carbohydrate
c. the carbon atoms in fats are fully oxidized to start with
d. carbohydrates cannot be oxidized
4. The phosphorylation of glucose to glucose-6-phosphate (G-6P)
a. is accompanied by formation of NADH
b. prevents that glucose molecule from being stored as glycogen
c. is catalyzed by an enzyme called an isomerase
d. traps the glucose inside the cell
5. Steps 1-3 of glycolysis convert glucose to fructose-1,6-bisphosphate (F-1,6-BP). These reaction types include
a. dehydrogenation, isomerization
b. phosphorylation, isomerization
c. phosphorylation, dehydration
d. cleavage, dehydrogenation
6. The energy yield of glycolysis is doubled
a. by hydrolysis of phosphosugars
b. by reducing C-O bonds
c. by rearranging DHAP to GAP
d. solely in the liver
7. During glycolysis, the oxidation of the aldehyde group in GAP (glyceraldehyde-3-phosphate)
a. is accompanied by production of ATP from ADP + Pi
b. is catalyzed by an enzyme called a kinase
c. is accompanied by reduction of NAD+ to NADH
d. does not change the number of carbon-oxygen bonds
8. Glycolysis makes an ATP profit
a. by storing glucose into glycogen for later use
b. without reduction of NAD+ to NADH
c. in step 10, conversion of PEP (phosphoenolpyruvate) to pyruvate
d. in step 1, conversion of glucose to G-6P (glucose-6-phosphate)
9. Under anaerobic conditions, yeast
a. converts pyruvate to ethanol to regenerate NAD+
b. converts pyruvate to lactate in two steps
c. stops performing glycolysis
d. converts pyruvate to PEP (phosphoenolpyruvate) with energy input
10. A unique feature of gluconeogenesis compared to glycolysis is
a. gluconeogenesis occurs primarily in muscle
b. gluconeogenesis begins with glucose and produces pyruvate
c. gluconeogenesis is not regulated
d. gluconeogenesis costs energy
11. During extreme conditions such as strenuous exercise, muscle and liver
a. both expend energy to synthesize glucose
b. both hydrolyze phosphosugars
c. cooperate by interconverting pyruvate and lactate
d. oxidize glucose aerobically
12. The overall process of gluconeogenesis can best be described as
a. glucose yields energy + reducing power
b. pyruvate + energy + reducing power yields glucose
c. pyruvate + reducing power yields ethanol + CO2
d. lactate + NAD+ yields pyruvate + NADH
13. Glycogen
a. is a branched polymer of glucose units
b. is found in trace amounts in liver cells
c. can be accessed anywhere in the chain by metabolic enzymes
d. involves metabolism that is unrelated to disease
14. Synthesis of glycogen
a. is a simple reversal of glycogen breakdown
b. requires activation of glucose-1-phosphate (G-1-P) to UDP-glucose
c. occurs without breakage of any high-energy phosphate bonds
d. never occurs in skeletal muscle
15. Glycogen breakdown
a. releases end units through a reaction called phosphorolysis
b. involves hydrolysis of phosphosugars
c. does not change any branch points in glycogen
d. requires ATP hydrolysis
16. The elongation of fatty acids is a repetition of three reactions adding carbons from malonyl ACP after each cycle until completion.
17. Fatty acid synthesis is different in bacteria than in eukaryotic cells because:
a. bacteria do not form malonyl CoA
b. eukaryotes use acetyl CoA to form malonyl CoA
c. bacteria do not form acetyl ACP
d. bacteria do not form acetoacetyl CoA
18. The first step in fatty acid synthesis is the formation of acetyl ACP from acetyl CoA and carbon dioxide.
19. Which of the following is not a stage of fatty acid synthesis?
a. condensation of precursors
b. dehydration
c. reduction
d. isomerization
20. Linoleate is an essential fatty acid in mammalian diets because mammalian cells do not have a desaturase that acts beyond the carbon-9 position.
21. Phosphatidate is an intermediate in the synthesis of triacylglycerols and glycerophospholipids.
22. Which of the following is a true statement, concerning HMG-CoA reductase?
a. It is regulated by covalent modification of a serine in its active site.
b. It catalyzes the first committed step in cholesterol biosynthesis.
c. It causes the production of NADPH.
d. The product of the reaction it catalyzes is acetoacetyl CoA.
23. Cholesterol is a precursor for each of the following, except
a. bile salts.
b. vitamin D.
c. testosterone.
d. vitamin C.
24. Which lipid form is transported across the inner mitochondrial membrane before β-oxidation?
a. acylcarnitine
b. fatty acyl CoA
c. acetoacetyl CoA
d. lysophospholipid CoA
25. Fatty acids are oxidized in the mitochondrial matrix.
26. What is the fate of most glycerol that is released during the hydrolysis of triacylglycerols from adipocytes?
a. It is transported to the kidneys and excreted in the urine.
b. It is used in the synthesis of sphingolipids.
c. It is converted to glucose via gluconeogenesis in the liver.
d. It is absorbed by the chylomicrons.
27. The main function of the bile salts is to transport lipids to the intestinal wall.
28. The largest lipoproteins are the chylomicrons.
29. Which do you expect to have the highest protein content by percent?
a. VLDLs
b. IDLs
c. HDLs
d. All of the lipids above have about the same protein content.
30. Which is not a ketone body?
a. dihydroxyacetone
b. acetoacetate
c. acetone
d. β-hydroxybutyrate