Single choice:
1. A
2. B
3. B
4. A
5. B
6. B
7. C
8. B
9. E
10. A
11. C
12. E
13. D
14. D
15. D
16. E
17. B
18. D
19. C
20. E
21. A
22. A
23. C
Part II
1. K
2. F
3. Z
4. G
5. T
6. I
7. H
8. Y
9. P
10. O
part III
1. Cellulose is a polymer of D-glucose units linked together by (β1->4)
linkages, whereas in the amylase polymer the linkages are of the (α->4)
configurations. The enzymes that hydrolyze amylase (amylase) are not active
with cellulose. Cellulose is not digested by number or by most other animals.
2. (a) C-1 becomes C-3 of glyceraldehyde-3-phosphate and subsequently
pyruvate. When pyruvate is decarboxylated and reduced to ethanol. C-3 of
pyruvate becomes the C-2 of ethanol (*CH3-CH2-OH).
(b) In order for all of the labeled carbon from glucose to be converted to
14CO2 during ethanol fermentation, the original label would have to be on C-3
or/and C-4 of glucose since these are converted to the carboxyl group of
pyruvate.
3.(a) In addition to binding sites for substrate(s), allosteric enzymes have
binding sites for regulatory metabolites. Binding of effectors to these
regulatory sites leads to a modification of enzyme activity by altering its
Vmax or Km value. ATP is both a substrate and an allosteric inhibitor of
PFK-1. Binding of ATP to the catalytic site increases activity, whereas
binding to allosteric site inhibits activity.
(b) Because ATP is a negative regulator of PFK-1, elevation of ATP when
energy is abundant inhibits the enzyme and thus the flux if metabolites
through the glycolytic pathway.
(c) The graph indicates that the addition of ADP suppresses the inhibition of
PFK-1 by ATP. Since the total adenine nucleotide pool is fairly constant in
all cells, utilization of ATP leads to an increase in ADP. The data indicates
that the activity of the enzyme may be regulated in vivo by the [ATP]/ [ADP].
4. (a) Treatment with the kinase and ATP converts glycogen phosphorylase to
the more active, phosphorylated form. Glycogen breakdown will accelerate.
(b) Treatment with the phosphatase converts active phosphorylase a to the
less active phosphorylase b. Glycogen breakdown will slow down.
5. (a) Succinate is converted by the citric acid cycle to fumarate by
Succinate dehydrogenase, then to malate by fumarase, then to oxaloacetate by
malate dehydrogenase. OAA can then leave the mitochondria via the
malate-aspartate shuttle, and is converted to PEP, which is glucogenic in the
cytosol.
(b) Glycerol is converted to glycerol-1-P by glycerol kinase, then by a
dehydrogenase (using NAD+) to dihydroxyacetone-P, which is glucogenic.
(c) Acetyl-CoA is not glucogenic. Higher animals do not have the enzymes to
convert it to pyruvate.
(d) Pyruvate is converted to oxaloacetate by pyruvate carboxylase, which us
used for gluconeogenesis as in (a).
(e) Butyrate is converted to butyryl-CoA by an acyl-CoA synthetase, and a
single turn of the β–oxidation pathway converts Butyryl-CoA to two
molecules of acetyl-CoA, which is not glucogenic.
6.(a) some bacteria or plants use the glyoxylate cycle to concert the fat to
glucose.
(b) Isocitrate Lyase and Malate Synthase
(c) 1. Seeds are rich in lipids, which contain fatty acids
2. During germination, plants use the acetyl-CoA produced in fatty acid
oxidation to produce oxaloacetate and other intermediates for carbohydrate
synthesis
3.Once plants begin photosynthesis and can fix CO2, glyoxysomes
disappear.
7. Make it as soon as possible to release the glucoses to produce the energy
when energy demands are high.
8. (a) 15
(b) 20
9. Fatty acid→ can produce water and energy
10. 1. acetoacetate , β-Hydroxybutyrate, acetone
2. diabetes and excessive intake of fats compared to carbohydrate.
11. Carnitine can help long-chain fatty acid enter the mitochondria to
process the β–oxidation.
12.Aspirin can inhibit the cyclooxygenase of the prostaglandin endoperoxide
synthase.
13. Glutamate
14. aldolase
15. isocitrate, Malate.
16. Cell can use the multiple enzyme complex to elevate the reaction
efficiency not the reaction rate.
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