85. If glucose labeled with ¹⁴C in C-1 were fed to yeast carrying out the ethanol fermentation, where would the ¹⁴C label be in the products?
(A) In C-1 of ethanol and CO₂
(B) In C-1 ofethanol only
(C) In C-2 (methyl group) of ethanol only
(D) In C-2 of ethanol and CO₂
(E) In COz only

81. Which of the following is the major site of expression for the monosaccharide transporter GLUT1? (A) erythrocytes, CNS, blood brain barrier (B) liver, pancreaticβ-cells, small intestine (C) neurons, testis, placenta (D) skeletal muscle, adipose tissue (E) small intestine, kidney, skeletal muscle, adipose tissue

82. Which of the following is/are the precursor(s) for the amino acid arginine? (A) glutamate, ammonia (B) glutamate (C) phenylalanine (D) methionine, serine (E) glutamine, or glutamate, aspartate

83. Fluroacetate is an inhibitor of aconitase in TCA cycle. Which of the following types of inhibition does fluroacetate belong to? (A) Irreversible inhibition (B) Competitive reversible inhibition (C) Mixed reversible inhibition (D) Uncompetitive reversible inhibition (E) None of the above

84. The complete oxidation of I mole of glucose generates about 30-32 moles of ATP synthesized from ADP. What is the reason for 2 moles ATP difference? (A) The reducing equivalent FADH2 is shuttled from cytosol into mitochondria via the dihydroxyacetone phosphate/glycerol-3-phosphate shuttle (B) The reducing equivalent NADH is shuttled from cytosol into mitochondria via the dihydroxyacetone phosphate/glycerol-3-phosphate shuttle (C) The reducing equivalent FADH2 is shuttled from cytosol into mitochondria via the malate/aspartate shuttle (D) The reducing equivalent NADH is shuttled from cytosol into mitochondria via the malate/aspartate shuttle (E) The reducing equivalent ATP is shuttled from cytosol into mitochondria via the malate/aspartate shuttle

86. Which of the following statements concerning the B oxidation of fatty acids is true? (A) About 1,200 ATP molecules are ultimately produced per 20-carbon fatty acid oxidized. (B) One FADH2 and two NADH are produced for each acetyl-CoA. (C) The free fatty acid must be carboxylated in the B position by a biotin-dependent reaction before the process of B oxidation commences. (D) The free fatty acid must be converted to a thioester before the process of B oxidation commences. (E) Two NADH are produced for each acetyl-CoA.

87. Which one of the following statements about the reverse transcriptases of retroviruses and the RNA replicases of other single-stranded RNA viruses, such as R17 and influenza virus, is correct? (A) Both enzymes can synthesize either RNA or DNA from an RNA template strand. (B) Both enzymes can utilize DNA in addition to RNA as a template strand. (C) Both enzymes carry the specificity for the RNA of their own virus. (D) Both enzymes have error rates similar to those of cellular RNA polymerases. (E) Both enzymes require host-encoded subunits for their replication function.

88 Ubiquitin-mediated protein degradation is a complex process, and many of the signals remain unknown. One known signal involves recognition of amino acids in a processed protein that are either stabilizing (Ala, Gly, Met, Ser, etc.) or destabilizing (Arg, Asp, Leu, Lys, Phe, etc.), and are located (A) a helix-turn-helix motif in the protein. (B) a lysine-containing target sequence in the protein. (C) the amino-terminus of the protein. (D) a zinc finger structure in the protein. (E) the carboxy-terminus of the protein.

89 Which of the following nonessential amino acids are synthesized from essential amino acids? (A) Glutamate and proline (B) Glutamate and phenylalanine (C) Tyrosine and cysteine (D) Cysteine and proline (E) Methionine and proline

90. Which of the following statements about drugs and inhibitors is TRUE? (A) Caffeine overdose can prevent sleep because it acts on adenine receptor. (B) Viagra is used to treat erectile dysfunction because it acts by increasing NO level. (C) Botulinum toxin is used to diminish facial glabellar lines because it acts by blocking voltage-gated Na+channel. (D) Lovastatin is used for lowering cholesterol because it acts by decreasing low-density lipoprotein level. (E) Aspirin is used to treat pain and fever because it acts reversibly by suppressing the cyclooxy genase.

42.Which of the following statement about the structure of sarcomeres in relaxed and contracted muscles is false? (A) The I bands form the borders of each sarcomere. (B) The A bands represent thick filaments. (C) The thin filaments are within the I bands and extend into the A bands. (D) In the contracted muscle, the I bands and H bands become shorter. (E) In the contracted muscle, the Z lines have moved closer together.