39. Which one is not a rate-limiting step in lipid metabolism?
(A) Carnitine acytransferase I for fatty acid entry into mitochondria
(B) Acetyl-CoA carboxylase for biosynthesis of fatty acid
(C) PEP carboxykinasc for triacylgiycerol cycle
(D) Acyl transferase for phospholipid synthesis
(E) HMG reductase for cholesterol synthesis

35. Which of the following statements is incorrect? (A) 2, 3, and 5 are incorrect. (B) 1, 3, and 4 are incorrect. (C) 1,3, and 5 are incorrect. (D) All are incorrect. (E) None is incorrect.

36. Which statement regarding glycogen breakdown is correct?  1. Cleavage of glycogen terminal glucose is catalyzed by glycogen phosphorylase.  2. The breaksdown of glycogen to generate Glucose-6-phosphate needs no ATP. 3. Transferase activity in glycogen debranching enzyme catalyzes the transfer of shorter α(1→)6 linked glucose chain to another o(1-)6 linked glucose chain for further cleavage reaction. 4. Glucosidase activity in glycogen debranching enzyme catalyzes the cleavage ofα(1→6) linked glucose for complete breaking down the branch in glycogen (A) 1, 2, and 3 are correct. (B) 2, 3, and 4 are correct. (C) 1, 2, and 4 are correct. (D) All are correct. (E) None is correct.

37. Which one of the following statements is incorrect? (A) P-type ATPase transporter is inhibited by vanadate. (B) Cyanide (CN-) blocks the lactose transporter in E.coli. (C) Tetradotoxin impairs voltage-gated Na+ channels. (D) Statin competes with acetyl Co-A. (E) Aspirin inhibits COX-2. pyruvatc

38. Which one is incorrect? (A) Catabolisin of fatty acids produces acetyl-CoA. (B) Catabolism of fatty acids produces reducing power NADH. (C) Anabolism of fatty acids requires acetyl-CoA and malonyl-CoA. (D) Anabolism of fatty acids requires reducing power from NADPH. (E) Fatty acid synthase contains a domain of acyl-CoA dehydrogenase.

40. Which of the following descriptions is(are) false?  1. The difference between a ribonucieotide and a deoxyribonucleotide is that a ribonucleotide has an --OH instead of an -H at C-2.  2. The DNA copies of mRNA found in a cDNA libtary are made by reverse transcriptase.  3. Type II restriction enzymes cleave DNA only at recognition sequences specific to a given restriction enzyme 4. Deamination of the nucleotide base 5-methylcytosine yields nucleotide base thymine. 5. Type II restriction enzymes may make staggered (off-center) cuts within their recognition scquences. (A) 5 only (B) 3 only (C) 4 only (D) 1 and 2 (E) Nonc of the descriptions are false.

41. Which of the following descriptions is false? (A) If clectron transfer in tightly coupled mitochondria is blocked (with antimycin A) between cytochrome b and cytochrome cl, O2 uptake will continue. (B) A drug that inhibits the ATP synthase in the mitochondrion will also inhibit the flow of electrons down the chain of carriers. (C) Oxidative phosphorylation can not occur in the absence of an intact inner mitochondrial membrance. (D) Uncoupling of mitochondrial oxidative phosphorylation haits mitochondrial ATP formation, but allows continued O2 consumption. (E) If electron transfer in tightly coupled mitochondria is blocked (with antimycin A) between cytochrome b and cytochrome cl, then all ATP synthesis will stop.

42. The reaction of the citric acid cycle that is most similar to the pyruvate dehydrogenase complex-catalyzed conversion of pyruvate to acetyl-CoA is the conversion of. (A) citrate to isocitrate. (B) fumarate to malate. (C) malate to oxaloacetate. (D) succinyi-CoA to succinate. (E) a-ketogiutarate to succinyl-CoA.

43. Which of the following statements in the enzyme cofactors involved in one-carbon transfer reactions is false? (A) Tetrahydrofolate, S-adenosylmethionine, and biotin are important cofactors involved in the reactions of one-carbon transfers. (B) S-Adenosylmethionine is synthesized from ATP and methionine. (C) In the activated-methyI cycle for the synthesis of methionine and S-adenosylmethionine, homocysteine is converted to methionine through the donation of the methy! group frommethylenetetrahydrofolate. (D) Acetyl-CoA carboxylase, which catalyzes the formation of malonyl-CoA from acetyl-CoA, contains a biotin prosthetic group. (E) The methyl group donated from S-adenosylmethionine is more reactive than that donated from N5-methyltetrahydrofolate.

44. What are the three mammalian enzymes that can "fix" ammonia into organic molecules? (A) Nitrogenase complex, CarbamoyI phosphate synthetase 1, and Glutamine synthetase (B) Glutamate dehydrogenase, Glutamine synthetase, and Carbamoyl phosphate synthetase I (C) Dinitrogenase, CarbamoyI phosphate synthetase I, and Gjutamate dehydrogenase (D) Dinitrogenase reductase, Dinitrogenase, and Carbamoy! phosphate synthetase 1 (E) Glutamine anidotransferases, Glutamine synthetase, and CarbamoyI phosphate synthetase 1

45. What are the major carriers of nitrogen in the blood for amino acid metabolism? (A) Alanine and glutamine (B) Arginine and glutamine (C) Lysine and arginine (D) Arginine and tryptophan (E) Glutamine and asparagine