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Chapter 27 Protein Metabolism Multiple Choice Questions 1. The genetic code Page: 1069 Difficulty: 2 Ans: C 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) 5,000. C) 30,000. D) 80,000. E) An upper limit cannot be determined from the data given. 2. The genetic code Page: 1069 Difficulty: 2 Ans: C Assuming that the average amino acid residue contributes 110 to the peptide molecular weight, what will be the minimum length of the mRNA encoding a protein of molecular weight 50,000? A) 133 nucleotides B) 460 nucleotides C) 1,400 nucleotides D) 5,000 nucleotides E) A minimum length cannot be determined from the data given. 3. The genetic code Pages: 1070-1074 Difficulty: 3 Ans: D Which of the following are features of the wobble hypothesis? A) A naturally occurring tRNA exists in yeast that can read both arginine and lysine codons. B) A tRNA can recognize only one codon. C) Some tRNAs can recognize codons that specify two different amino acids, if both are nonpolar. D) The wobble occurs only in the first base of the anticodon. E) The third base in a codon always forms a normal Watson-Crick base pair. 4. The genetic code Page: 1069 Difficulty: 2 Ans: C Which one of the following is true about the genetic code? A) All codons recognized by a given tRNA encode different amino acids. B) It is absolutely identical in all living things. C) Several different codons may encode the same amino acid. D) The base in the middle position of the tRNA anticodon sometimes permits wobble base pairing with 2 or 3 different codons. E) The first position of the tRNA anticodon is always adenosine. Chapter 27 Protein Metabolism 5. Protein synthesis Pages: 1076-1077 Difficulty: 1 Ans: D Which one of the following statements about ribosomes is true? A) The large subunit contains rRNA molecules, the small subunit does not. B) The RNA in ribosomes plays a structural, not catalytic, role. C) There are about 25 of them in an E. coli cell. D) There are two major subunits, each with multiple proteins. E) They are relatively small, with molecular weights less than 10,000. 6. Protein synthesis Pages: 1079-1080 Difficulty: 2 Ans: A Which of the following statements about tRNA molecules is false ? A) A, C, G, and U are the only bases present in the molecule. B) Although composed of a single strand of RNA, each molecule contains several short, double- helical regions. C) Any given tRNA will accept only one specific amino acid. ... View Full Document

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