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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