52. Myoglobin and the subunits of hemoglobin have______ .
(A) no obvious structural relationship
(B) very different primary and tertiary structures
(C) very similar primary and tertiary structures
(D) very similar primary structures, but different tertiary structures
(E) very similar tertiary structures, but different primary structures

48. A biochemist is attempting to separate a protein X from protein C in a solution. The proteins have the following properties: What type of protein separation techniques might be the best one to separate protein X from protein C? (A) Gel filtration (B) SDS-polyacrylamide gel electrophoresis (C) Affinity chromatography (D) Ion-exchanger chromatography (E) Agarose gel electrophoresis

49. A sequence of amino acids in a certain protein is found to be –Ser–Gly–Pro–Gly–. The sequence is most probably part of a(n)______. (A) β-turn (B) parallel β-sheet (C) α-helix (D) α-sheet (E) antiparallel β-sheet

50. Which of the following is (are) true of the oxidation of 1 mol of palmitate (a 16-carbon saturated fatty acid； 16:0) by the β-oxidation pathway, beginning with the free fatty acid in the cytoplasm?①Activation of the free fatty acid requires the equivalent of two ATPs.② Inorganic pyrophosphate (PPi) is produced.③Carnitine functions as an electron acceptor.④8 mol of FADH2 are formed.⑤8 mol of acetyl-CoA are formed.⑥There is no direct involvement of NAD+ . (A)①and⑤ (B) ①②and⑤(C) ①② and⑥ (D) ①③ and ⑤ (E)④ and⑤

51. Which of the following peptides is more likely to be nuclear targeting signal? (A) ser-ser-thr-asn-arg-lys-met-thr (B) arg-lys-lys-arg-arg-lys-leu-met (C) met-leu-ile-phe-leu-met-ile-ile (D) ser-ser-thr-thr-thr-thr-ser-thr-ser (E) asn-lys-ser-asn-lys-ser-asn-lys-ser

53. Which one of the following analytical techniques does not help illuminate a gene’s cellular function? (A) Southern blotting (B) DNA microarray analysis (C) Protein chip analysis (D)Two-dimensional gel electrophoresis (E) Two-hybrid analysis

54. Hormone-activated phospholipase C can convert phosphatidylinositol 4,5-bisphosphate to______ . (A) diacylglycerol + inositol triphosphate (B) diacylglycerol + inositol+ phosphate (C) glycerol + inositol + phosphate (D) glycerol + phosphoserine (E) phosphatidyl glycerol + inositol + phosphate

55. Oxidative phosphorylation and photophosphorylation share all of the following except______  . (A) chlorophyll (B) involvement of cytochromes (C) participation of quinones (D) proton pumping across a membrane to create electrochemical potential (E) use of iron-sulfur proteins

56. A certain bacterial mRNA is known to represent only one gene and to contain about 800 nucleotides. If you assume that the average amino acid residue contributes 110 to the peptide molecular weight, the largest polypeptide that this mRNA could code for would have a molecular weight of about ______ . (A) 800 (B) 30,000 (C) 5,000 (D) 80,000 (E) An upper limit cannot be determined from the data given

57. Which of the following statements about the polymerase chain reaction (PCR) is false? (A) DNA amplified by PCR can be cloned. (B) DNA is amplified at many points within a cellular genome. (C) Newly synthesized DNA must be heat-denatured before the next round of DNA synthesis begins. (D) The boundaries of the amplified DNA segment are determined by the synthetic oligonucleotides used to prime DNA synthesis. (E) The technique is sufficiently sensitive that DNA sequences can be amplified from a single animal or human hair.

58. Which of the following is not true of the citric acid cycle? (A) All enzymes of the cycle are located in the cytoplasm, except succinate dehydrogenase, which is bound to the inner mitochondrial membrane. (B) In the presence of malonate, one would expect succinate to accumulate. (C) Oxaloacetate is used as a substrate but is not consumed in the cycle. (D) Succinate dehydrogenase channels electrons directly into the electron transfer chain. (E) The condensing enzyme is subject to allosteric regulation by ATP and NADH.