複選題

41. A characteristic of the glycerophosphate shuttle is:
(A) It shuttles NADH across the mitochondrial membrane to yield 2.5 ATP/ADH.
(B) It shuttles "NADH electron equivalents" across the mitochondrial membrane to yield 1.5 ATP/NADH.
(C) It only operates efficiently when the [NADH] in the cytoplasm is higher than in the matrix.
(D) Malate is a key component in the shuttle process.
(E) Aspartate is a key component in the shuttle process.

37. Which of these statements about the membrane proteins is   true  ? (A) An integral membrane protein can be extracted with a chelating agent that removes divalent cations. (B) Peripheral membrane proteins are generally noncovalently bound to membrane lipids. (C) Carbohydrate moieties of membrane glycoproteins are linked to the intracellular domain of the proteins. (D) Peripheral membrane proteins may have functional units on both sides of the membrane. (E) Glycosylphosphatidylinositols, abbreviated GPI, are complex glycolipids that attach some proteins to the cytosolic surface of the plasma membrane.

38. In amino acid catabolism, the first reaction for many amino acids is a(n): (A) oxidative deamination requiring . (B) hydroxylation requiring NADPH and O2. (C) transamination requiring pyridoxal phosphate (PLP). (D) reduction requiring pyridoxal phosphate (PLP). (E) decarboxylation requiring thiamine pyrophosphate (TPP).

39. Which of the following is   not   true about cyclic electron flow of photophosphorylation? (A) Cyclic electron flow produces more NADPH per photon than noncyclic electron flow. (B) Cyclic electron flow involves only photosystem I. (C) Plastocyanin is required for cyclic electron flow. (D) Cyclic electron flow leads to the build-up of a proton gradient. (E) Cyclic electron flow does not produce O2.

40. Which of the following statements about mitochondrial transport systems is correct? (A) Malate-aspartate shuttle: converts cytosolic NADH to mitochondrial FADH2. (B) ATP-ADP translocase: transfers ATP and a proton from matrix to cytosol while transferring ADP from cytosol to matrix. (C) Glycerophosphate shuttle: converts cytosolic FADH2 to mitochondrial NADH. (D) The malate-aspartate shuttle is irreversible while the glycerophosphate shuttle is reversible. (E) None of the above are correct.

42. Which of the following correctly and completely describes electron movement in electron transport? (A) NADH → complex I → complex III → coenzyme Q→ Complex IV → O2 (B) [FADH2] → complex II → cytochrome c → complex III → coenzyme Q → Complex IV → O2 (C) NADH → complex I → coenzyme Q→ complex III -~-→ cytochrome c → Complex IV → O2 (D) [FADH2] → complex I → coenzyme Q→ complex III → Complex IV → O2 (E) None of the above

43. Glutamine synthetase plays an important role in the incorporation of ammonia (or ammonium ions) into glutamine. Which of the following mechanisms of covalent modification controls the activity of glutamine synthetase? (A) Phosphorylation/dephosphorylation. (B) Adenylation/deadenylation. (C) Acetylation/deacetylation. (D) Methylation/demethylation. (E) None of the above.

44. Most cancers depend on a high rate of aerobic glycolysis for their continued growth and survival. Paradoxically, some cancer cell lines also display addiction to glutamine. Which of the following is   not   true for the possible mechanism behind this glutamine addiction: (A) Glutamine is an essential amino acid. (B) Glutamine provides nitrogen for nucleotide synthesis. (C) Glutamine provides substrate for mitochondrial citric acid cycle. (D) Glutamine provides nitrogen for protein synthesis. (E) Glutamine activates mTORC1 signaling.

45. Insulin resistance causes an increase in gluconeogenic activity in the liver due to the lack of glucose. What serves as the primary carbon source for gluconeogenesis under these conditions? (A) Amino acids. (B) Glycerol. (C) Fructose. (D) Acetyl-CoA. (E) Ketone bodies

46. Considered the following transamination reaction in amino acid biosynthesis, what amino acid would be produced? (A) Glu. (B) Asp. (C) Gln. (D) Asn. (E) Arg.

47. Given the saturated fatty acid shown below, how many ATPs can be produced when it is completely metabolized by β-oxidation? Some useful info:  i. In the TCA cycle, one Acetyl-CoA gives 3 NADHs, 1 FADH2, and 1 GTP. ii. One NADH produces 2.5 ATPs. iii. One FADH2 produces 1.5 ATPs. (A) 50. (B) 52. (C) 60. (D) 62. (E) 64.