16. The immediate reducing power of ribonucleotide reductase is provided by:
(A) Thioredoxin.
(B) Ferredoxin.
(C) NADH.
(D) Fe-S complex.
(E) Cyt P-450.

12. Which one is   not   required for fatty acid synthesis? (A) NADPH. (B) NADH. (C) Acetyl Co-A. (D) Malonyl-CoA. (E) Fatty acid synthase.

13. Which one does  not  utilize cytoplasmic fatty acid as a primary precursor? (A) Cholesterol. (B) Triacylglycerides. (C) Phosphoglycerides. (D) Sphingolipid. (E) Prostaglandin.

14. Which one does   not   contribute to cytoplasmic fatty acid pool? (A) Palmitic acid. (B) LDL receptor. (C) FA transport proteins or FA translocase. (D) FA binding proteins (FABPs). (E) Arachidonic acid.

15. Which one is  not  correct regarding β-oxidation? (A) Activation of fatty acid by coupling to CoA, followed by transfer of the acyl group to carnitine palmitoyltransferase 1. (B) Acylcarnitine is shuttled to the mitochondrial matrix by the carnitine-acylcarnitine translocase. (C) The acyl chain is transferred back to CoA by carnitine palmitoyltransferase 2. (D) Very long fatty acids require initial shortening in the cytoplasm. (E) 16-carbon fatty acid palmitate yields approximately 130 molecules of ATP.

17. Which of the following hormones affects the arcuate nucleus of the hypothalamus and ultimately results in an inhibition of nutrient intake? (A) Adiponectin. (B) Leptin. (C) Ghrelin. (D) Gucagon. (E) None of the above.

18. The reaction, glutamate + + a-ketoglutarate + NAD(P)H + , is catalyzed by: (A) Nitrogenase. (B) Carbamoyl-phosphate synthetase (CPS-I). (C) Glutamate dehydrogenase (GDH). (D) Glutamine synthetase (GS). (E) None are true.

19. Nitroglycerine is a potent _____ because of the release of _____(A) antioxidant； O2 (B) vasoconstrictor； NO. (C) vasodilator； NO. (D) muscle tensor； O2 (E) All are true

20. By definition of a Lewis acid, choose the correct answer. 1. 2. 3. 4. NH35. (A) 1 and 3 are Lewis acids. (D) 1 and 4 are Lewis acids. (B) 2 and 4 are Lewis acids. (E) 2 and 3 are Lewis acids. (C) 5 is Lewis acid.

21. What enzyme breaks apart the hydrogen bonds between two strands of DNA? (A) Polymerase I. (B) Polymerase III. (C) Ligase. (D) Helicase. (E) Okazaki.

22. Which statement about the elongation of the lagging strand during DNA replication is correct? (A) It is synthesized in a 3' 5' direction. (C) It requires a short RNA primer to proceed. (B) It progresses (grows) toward the replication fork. (D) It is synthesized by DNA ligase. (E) It is synthesized continuously.