Question 1

Which of the following is NOT a characteristic exhibited by aminoacyl-tRNA synthetases?

Accepted Answer

A) Some are monomeric and others are oligomeric. 
B) They attach the amino acid to the 2'- or the 3'-hydroxyl of the ribose located at the 5'-end of the tRNA. 
C) They attach the amino acid to a terminal adenylate residue on the tRNA. 
D) Through binding specificity,they relate specific amino acids to appropriate codons. 
A) Some are monomeric and others are oligomeric. 
B) They attach the amino acid to the 2'- or the 3'-hydroxyl of the ribose located at the 5'-end of the tRNA. 
C) They attach the amino acid to a terminal adenylate residue on the tRNA. 
D) Through binding specificity,they relate specific amino acids to appropriate codons.

Question 2

The genetic code is said to be degenerate.What does this imply?

Accepted Answer

A) Each codon codes for more than 1 amino acid. 
B) An anticodon can interact with more than 1 codon in the mRNA in which the codon may differ in any or all of the 3 nucleotides. 
C) Most amino acids are coded for by more than 1 codon. 
D) The code is universally used by virtually all species. 
A) Each codon codes for more than 1 amino acid. 
B) An anticodon can interact with more than 1 codon in the mRNA in which the codon may differ in any or all of the 3 nucleotides. 
C) Most amino acids are coded for by more than 1 codon. 
D) The code is universally used by virtually all species.

Question 3

Which of the following is NOT a characteristic of the genetic code?

Accepted Answer

A) Each single amino acid is represented by several codons. 
B) Codons are read 5' to 3'. 
C) There are 20 total "sense" codons,1 for each amino acid. 
D) There are 3 nonsense codons;these are "stop" signals. 
A) Each single amino acid is represented by several codons. 
B) Codons are read 5' to 3'. 
C) There are 20 total "sense" codons,1 for each amino acid. 
D) There are 3 nonsense codons;these are "stop" signals.

Question 4

Which of the following is NOT a characteristic of eukaryotic mRNA?

Accepted Answer

A) poly(
A) tail 
B) no Shine-Dalgarno sequence 
C) codon binding directs for an initiator tRNA carrying met 
D) 5'-7methyl-GTP cap 
A) poly(
A) tail 
B) no Shine-Dalgarno sequence 
C) codon binding directs for an initiator tRNA carrying met 
D) 5'-7methyl-GTP cap

Question 5

Which of the following is NOT an anatomical characteristic of the 30S subunit of E.coli ribosomes?

Accepted Answer

A) "head" 
B) "body" or "base" 
C) "platform" 
D) "legs" 
A) "head" 
B) "body" or "base" 
C) "platform" 
D) "legs"

Question 6

Which of the following is NOT a basic step in protein synthesis?

Accepted Answer

A) The elongation reaction transfers the peptide chain from the peptidyl-tRNA in the A site to the aminoacyl-tRNA in the P site. 
B) The P site is occupied by peptidyl-tRNA carrying the growing polypeptide chain. 
C) Binding of mRNA by the small subunit is followed by association of a particular initiator aminoacyl-tRNA that recognizes the first codon. 
D) The new,longer peptidyl-tRNA moves from the A site into the P site as the ribosome moves one codon further along the mRNA. 
A) The elongation reaction transfers the peptide chain from the peptidyl-tRNA in the A site to the aminoacyl-tRNA in the P site. 
B) The P site is occupied by peptidyl-tRNA carrying the growing polypeptide chain. 
C) Binding of mRNA by the small subunit is followed by association of a particular initiator aminoacyl-tRNA that recognizes the first codon. 
D) The new,longer peptidyl-tRNA moves from the A site into the P site as the ribosome moves one codon further along the mRNA.

Question 7

Which nucleophile is employed by the peptidyl transferase-catalyzed reaction?

Accepted Answer

A) oxygen in the carboxylate group of the aminoacyl-tRNA 
B) amino nitrogen in the aminoacyl-tRNA 
C) amino nitrogen from the peptidyl-tRNA 
D) oxygen in the carboxylate group of the peptidyl-tRNA 
A) oxygen in the carboxylate group of the aminoacyl-tRNA 
B) amino nitrogen in the aminoacyl-tRNA 
C) amino nitrogen from the peptidyl-tRNA 
D) oxygen in the carboxylate group of the peptidyl-tRNA

Question 8

Which amino acids are rich in ribosomal proteins and serve to interact with polyanionic RNAs?

Accepted Answer

A) Arg and Lys 
B) Asp and Ala 
C) Lys and Ala 
D) Ala and Arg 
A) Arg and Lys 
B) Asp and Ala 
C) Lys and Ala 
D) Ala and Arg

Question 9

Which amino acid residue is used at the beginning of protein synthesis in bacterial cells?

Accepted Answer

A) methionine 
B) formylmethionine 
C) cysteine 
D) phosphoserine 
A) methionine 
B) formylmethionine 
C) cysteine 
D) phosphoserine

Exam 30: Protein Synthesis

Which of the following is NOT a characteristic exhibited by aminoacyl-tRNA synthetases?

The genetic code is said to be degenerate.What does this imply?

Which of the following is NOT a characteristic of the genetic code?

Which of the following is NOT a characteristic of eukaryotic mRNA?

Which of the following is NOT an anatomical characteristic of the 30S subunit of E.coli ribosomes?

Which of the following is NOT a basic step in protein synthesis?

Which nucleophile is employed by the peptidyl transferase-catalyzed reaction?

Which amino acids are rich in ribosomal proteins and serve to interact with polyanionic RNAs?

Which amino acid residue is used at the beginning of protein synthesis in bacterial cells?

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Lipid Biosynthesis

Membranes and Membrane Transport

The Reception and Transmission of Extracellular Information

Enzymes Kinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Nutrition and the Organization of Metabolism

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Nitrogen Acquisition and Amino Acid Metabolism

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Synthesis and Degradation of Nucleotides

Recombinant Dna: Cloning and Creation of Chimeric Genes

DNA Metabolism: Replication, recombination, and Repair

Transcription and the Regulation of Gene Expression

Post-Transcriptional Regulation of Gene Expression

Completing the Protein Life Cycle: Folding, processing, and Degradation

Metabolic Integration and Organ Specialization

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