14. All of the following compounds are intermediates of the Kreb cycle except_______ .
(A) isocitrate
(B) malate
(C) oxaloacetate
(D) pyruvate
(E) succinate

10. Cholesterol can act as a precursor for each of the following compounds except_____ . (A) chenodeoxycolic acid (B) 1,25-dihydroxycholecalciferol (C) testosterone (D) glycocholic acid (E) cholecystokinin

11. The p53 gene (tumor suppressor gene) product is_____. (A) a G protein (B) a DNA-binding protein (C) a tyrosine kinase (D) a serine/threonine kinase (E) a GTPase

12. Pyridoxal phosphate is a cofactor for which of the following enzymatic reaction? (A) Fixation of carbon dioxide. (B) Oxidation-reduction. (C) Aminotransferase. (D) Phosphate group transfer. (E) Isomerase.

13. Which of the following enzymes converts stearoyl-CoA to oleoyl-CoA? (A) △ 5 desaturase. (B) △ 6 desaturase. (C) △ 7 desaturase. (D) △8 desaturase. (E)△9 desaturase.

15. If the numbering of fatty acids in the carboxyl carbon is number 1, which carbon in palmitic acid is oxidized during the first cycle of E-oxidation? (A) 1 (B) 2 (C) 3 (D) 4 (E) 15

16. The following techniques could be potentially employed as a tool in gene therapy except_______ . (A) RNAi (B) Antisense DNA (C) Triplex DNA (D) Ribozyme (E) DNA bending 

17. In glycoproteins, the carbohydrate moiety is always attached through the amino acid residues_______. (A) tryptophan, aspartate or cysteine (B) asparagine, serine or threonine (C) glycine, alanine or aspartate (D) aspartate or glutamate (E) glutamine or arginine

18. Sphingosine is not a component of_______. (A) cardiolipin (B) ceramide (C) cerebrosides (D) gangliosides (E) sphingomyelin

19. The ion channel that opens in response to acetylcholine is an example of a ____________ signal transduction system. (A) G protein (B) ligand-gated (C) receptor-enzyme (D) serpentine receptor (E) voltage-gated

20. A monoclonal antibody differs from a polyclonal antibody in that monoclonal antibodies_______. (A) are labeled with chemicals that can be visualized (B) are produced by cells from the same organism that produced the antigen (C) are synthesized by a population of identical, or “cloned” cells (D) are synthesized only in living organisms (E) have only a single polypeptide chain that can recognize an antigen