12. In the lac operon, the CAP (cyclic AMP activator protein)-cAMP complex functions as:
(A) A positive regulator
(B) An operator
(C) A repressor
(D) All are wrong

8. Which of the below is NOT involved in intron removal and the processing of mRNA precursors into mRNA? (A) U2 snRNA (B) U3 snRNA (C) U4 SRNA (D) U6 snRNA

9. Which one of the following descriptions about mutations is WRONG? (A) An adenosine replaced by a cytidine is a "transversion" mutation. (B) An adenosine replaced by a guanosine is a "transition" mutation. (C) A nonsense mutation results in a different amino acid being inserted in the protein. (D) Silent mutation means a change at the DNA level that does not result in any change of amino acid in the encoded protein.

10. Which of the following product will be synthesized in platelets and upon release cause vasoconstriction and platelet aggregation? (A) Thromboxanes (B) Prostacyclins (C) Leukotrienes (D) Lipoxins

11. Prostanoids are synthesized by: (A) Pentose phosphate pathway (B) B-oxidation pathway (C) Lipoxygenase pathway (D) Cyclooxygenase pathway

13. The transcribed sequences complementary to the coding sequences above are:  5'-ACTGTATCGGAT-3' (coding)  3'-TGACATAGCCTA-5' (A) 5'-ACTGTATCGGAT-3' (B) 5'-ACUGUAUCGGAU-3' (C) 5'-ATCCGATACAGT-3' (D) 5'- AUCCGAUACAGU-3'

14. Which one of the following descriptions is WRONG? (A) Caffeine is a trimethylxanthine. (B) Theophylline is a dimethylxanthine. (C) Theobromine is the bypoxanthine derivative of cocoa. (D) Theobromine and theophylline are similar but lack the methyl group at N-1 and at N-7, respectively.

15. Which one of the following subunits is NOT contained in the basic DNA-dependent RNA polymerase of the bacterium Escherichia coli? (A) α subunit (B) β subunit (C) ω subunit (D) σ subunit

16. Which of the following descriptions about apolipoproteins is CORRECT? (A) Apo A-I is the ligand for LDL receptor, while Apo B-100 binds to HDL receptor. (B) Nascent VLDL and nascent chylomicron both contain Apo C and E. (C) Apo C-II serves as the enzyme cofactor of lipoprotein lipase. (D) Apo B-48 on VLDL and Apo B-100 on LDL were encoded from two different genes, and the peptide sequence homology are about 70%. (E) Apo B-100 contains LDL receptor binding domain, but Apo-E cannot bind to LDL receptor.

17. Which of the following descriptions about acylglycerol and sphingolipid synthesis is CORRECT? (A) In adipose tissue, glycerol 3-phosphate is synthesized by the phosphorylation of glycerol. (B) Glycerol 3-phosphate is phosphorylated by glycerol kinase, and there is no alternative synthesis pathway from glycolysis. (C) Glycerol 3-phosphate acyltransferase is the rate limiting step of triacylglycerol synthesis. (D) Phosphatidylcholine synthesis involve ADP-activated choline. (E) All sphingolipids are formed from ceremide.

18. Which of the following statements about lipoproteins is INCORRECT? (A) High density lipoproteins (HDL) absorbs cholesterol and carries it back to the liver. (B) Chylomicrons are mainly composed of cholesterol absorbed from the gut. (C) Very low density lipoprotein (VLDL) are large triglyceride-rich lipoproteins produced in liver. (D) Low density lipoproteins (LDL) are the main transporters of cholesterol in the blood, carry cholesterol from the liver to cells throughout the body. (E) Intermediate density lipoproteins (IDL) are derived from VLDL after removal of triacylglycerol.