415 exam 3 MC questions - 1 Chapter 22 1 The cleavage of...

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Chapter 22 1. The cleavage of tryglycerides into glycerol and fatty acids is performed by lipases. The signaling process initiating the activation of lipases is a. the same as that which signals the cell to breakdown glycogen b. the same as that which signals the cell to shut down the citric acid cycle c. the same as that which signals the initiation of gluconeogenesis Correct. The same steps and signals (up to protein kinase A) are involved in activation of both processes. 2. The glycerol produced during the lipolysis of triglycerides a. is a waste product that is excreted from cells b. is stored within the cell for future synthesis of tryglycerides c. can be used as either a source of energy or for gluconeogenesis Correct. Phosphorylation and oxidation of glycerol produces glyceraldehyde-3-phosphate that can be degraded via the glycolytic pathway and citric acid cycle to generate ATP or be converted to glucose via gluconeogenesis. 3. Fatty acids are activated by attachment to Coenzyme A at the outer mitochondrial membrane, but the resulting fatty acyl-Coenzyme A is not degraded until it reaches the mitochondrial matrix. The fatty acyl-Coenzyme A a. freely crosses the inner mitochondrial membrane due to its hydrophobic character. b. is reconverted to the free fatty acid on one side of the inner mitochondrial membrane, which is reattached to Coenzyme A on the other side of the membrane. c. is transferred to another molecule that is involved in transport of the fatty acid into the mitochondrial matrix. Correct. Fatty acids are transferred from Coenzyme A to carnitine, which transports them across the inner mitochondrial membrane and then transfers them back to Coenzyme A. 4. The degradation of an 18-carbon saturated fatty acid would be expected to yield how many NADH and FADH2 per fatty acid molecule? a. 7 b. 8 c. 9 Correct. Eight cycles of the beta-oxidation pathway are required to degrade a fatty acid to acetyl- Coenzyme A with one NADH and FADH2 being produced in each cycle. 5. During the degradation of unsaturated fatty acids, the double bonds must be reduced. The reductant for this process is a. FADH2 formed during in other steps of fatty acid degradation b. NADH formed during in other steps of fatty acid degradation c. NADPH Correct. The enzyme involved in reduction of double bonds during fatty acid degradation is specific for NADPH as its electron donor. 6. Animals are not capable of converting fatty acids into glucose because a. They cannot convert acetyl-Coenzyme A into pyruvate to initiate the gluconeogenesis pathway b. Fatty acid degradation through the citric acid cycle does not lead to a net increase in oxaloacetate c. Fatty acid degradation does not produce sufficient energy in the form of ATP to drive gluconeogenesis 1
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Correct. Two carbons enter the cycle in the form of acetyl-Coenzyme A and two carbons are lost as CO2 such that there is no net increase in oxaloacetate. 7. Which of the following is NOT a difference in the pathways by which fatty acids are degraded and
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This note was uploaded on 04/01/2008 for the course BIOLCHEM 415/515 taught by Professor Ballou during the Winter '08 term at University of Michigan.

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415 exam 3 MC questions - 1 Chapter 22 1 The cleavage of...

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