42. Glucose breakdown in certain mammalian and bacterial cells can occur by mechanisms other than classic glycolysis. In most of these, glucose 6-phosphate is oxidized to 6-phosphogluconate, which is then further metabolized by:
(A) an aldolase-type split to form glyceric acid and glyceraldehyde 3-phosphate.
(B) an aldolase-type split to form glycolic acid and erythrose 4-phosphate.
(C) conversion to 1,6-bisphosphogluconate.
(D) decarboxylation to produce keto- and aldopentoses.
(E) oxidation to a six-carbon dicarboxylic acid.

38. The urea cycle and citric acid cycle are linked by(A) arginine and fumarate. (B) citrulline and ornithine.(C) fumarate and aspartate.(D) omnithine and arginine. (E) citrulline and argininosuccinate.

39. Approximately how many ATP molecules are netted from the complete oxidation of stearic acid (C-18)?(A) 2 (B) 4 (C) 32 (D) 88 (E) 120

40. Gout is caused by high levels of uric acid. What are the possible causes?(A) Glucose-6-phosphatase deficiency(B) Phosphoribosylpyrophosphate (PRPP) synthetase mutation(C) Hypoxanthine-guanine phosophoribosyItransferase (HGPRT) deficiency(D) All of these are possible causes.(E) None of the above.

複選題41. What situation is most likely to cause the formation of ketone bodies?(1) Starvation (2) Gout (3) High in lipid diet (4) Regular meal(5) High in carbohydrate diets (6) Diabetes(7) Exercising (8) Intake of short-chain fatty acids (A) 1,2, and 3 (B) 3, 4, and 7 (C) 5,6, and 7 (D) 2, 4, and 8(E) 1, 6, and 8

43.______ is often used in carboxylation reactions while________ is often used in decarboxylation reactions.(A) thiamine pyrophosphate; lipoate (B) lipoate; biotin (C) biotin; thiamine pyrophosphate(D) pyridoxal-5-phosphate; biotin (E) lipoate; pyridoxal-5-phosphate

44. In the citric acid cycle, citrate is isomerized to isocitrate by aconitase. H2O was first abstracted from citrate, and then rehydrated with H- and HO–adding back in opposite positions to produce isocitrate. This reaction catalyzed by aconitase is quite stereospecific. As citrate has a total of four chemically equivalent hydrogens (labeled as H1~H4 in the figure), only one of the four hydrogens, the pro-R H atom of the pro-R arm of citrate, is abstracted during the reaction of theH2O abstraction by aconitase.Which one of the hydrogens in the citrate molecule shown in the figure is the pro-R H atom of the pro-R arm?(A) H1 (B) H2 (C) H3 (D)H4 (E) None of them.

45. Which of the following monosaccharides is an aldose?(A)a(B) b (C)c (D)d (E) None of the above.

46. The ratio of NADP+/NADPH in liver runs about 1/67 which means that:(A) it is similar to the ratio of NAD+/NADH.(B) glucose-6-phosphate dehydrogenase will be turned on most of the time.(C) glucose-6-phosphate is rate limiting for pentose phosphate pathway.(D) glucose-6-phosphate preferentially goes to the pentose phosphate pathway.(E) glucose-6-phosphate dehydrogenase activity is dependent upon use of some of the NADPH before activity increases.

47. In an anaerobic muscle preparation, lactate formed from glucose labeled in C-2 would be labeled in:(A) all three carbon atoms.(B) only the carbon atom carrying the OH.(C) only the carboxyl carbon atom.(D)only the methyl carbon atom.(E) the methyl and carboxyI carbon atoms.

48. In the glycolytic pathway, there is an isomerization of glucose 6-phosphate to fructose 6-phosphate occurs two steps before the C-C bond cleavage reaction between C3 and C4 to produce two three-carbon sugars. Where would the bond cleavage occur if there is no preceding isomerization?(A) Without isomerization, bond cleavage would occur between C2 and C3.(B) Without isomerization, bond cleavage would occur between C3 and C4.(C) Without isomerization, bond cleavage would occur between C4 and C5.(D) Without isomerization, bond cleavage would occur between C5 and C6.(E) Without isomerization, bond cleavage would occur between C1 and C2.