Question 1

Termination of translation in prokaryotic cells requires:

Accepted Answer

A)  binding of the terminator tRNA to the termination codon. 
B)  interaction of release factors with the termination codon. 
C)  ternary interaction of the release factor and the termination tRNA with the termination codon. 
D)  release factor interaction with the Shine-Dalgarno sequence and subsequent dissociation of the two ribosomal subunits. 
E)  displacement of EF-G by EF-Tu:aminoacyl-tRNA. 
A)  binding of the terminator tRNA to the termination codon. 
B)  interaction of release factors with the termination codon. 
C)  ternary interaction of the release factor and the termination tRNA with the termination codon. 
D)  release factor interaction with the Shine-Dalgarno sequence and subsequent dissociation of the two ribosomal subunits. 
E)  displacement of EF-G by EF-Tu:aminoacyl-tRNA. B

Question 2

The central domain of the ____S ribosomal subunit serves as the decoding center and is composed only of ____S rRNA.

Accepted Answer

A)  30; 16 
B)  30; 5 
C)  50; 23 
D)  50; 5 
E)  none are true 
A)  30; 16 
B)  30; 5 
C)  50; 23 
D)  50; 5 
E)  none are true A

Question 3

The genetic code has all of the following characteristics EXCEPT:

Accepted Answer

A)  It is degenerate. 
B)  It is read 3' to 5'. 
C)  It is read from a fixed starting point without punctuation. 
D)  It is not overlapping. 
E)  A group of three bases codes for one amino acid. 
A)  It is degenerate. 
B)  It is read 3' to 5'. 
C)  It is read from a fixed starting point without punctuation. 
D)  It is not overlapping. 
E)  A group of three bases codes for one amino acid. B

Question 4

All are characteristics of eukaryotic mRNA EXCEPT:

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

Question 5

Intact 70S ribosomes are ____ in initiation of protein synthesis because ____ 30S subunits can interact with initiation factors.

Accepted Answer

A)  active; bound 
B)  inactive; only free 
C)  active; open 
D)  inactive; mRNA bound 
E)  all are true 
A)  active; bound 
B)  inactive; only free 
C)  active; open 
D)  inactive; mRNA bound 
E)  all are true

Question 6

Mitochondrial and chloroplastic ribosomes resemble ____ ribosomes.

Accepted Answer

A)  prokaryotic 
B)  lower eukaryotic 
C)  higher eukaryotic 
D)  no other 
E)  none are true 
A)  prokaryotic 
B)  lower eukaryotic 
C)  higher eukaryotic 
D)  no other 
E)  none are true

Question 7

Protein biosynthesis in all cells utilizes energy driving the assembly process provided by ____ hydrolysis.

Accepted Answer

A)  ATP 
B)  GTP 
C)  UTP 
D)  CTP 
E)  None of the above 
A)  ATP 
B)  GTP 
C)  UTP 
D)  CTP 
E)  None of the above

Question 8

The actual peptide bond-forming step in translation is referred to as ____, and is catalyzed by ____.

Accepted Answer

A)  peptide bond-formation; peptidase 
B)  transpeptidation; transpeptidase 
C)  peptidyl transfer; peptidyl transferase 
D)  translocation; translocase 
E)  none of the above 
A)  peptide bond-formation; peptidase 
B)  transpeptidation; transpeptidase 
C)  peptidyl transfer; peptidyl transferase 
D)  translocation; translocase 
E)  none of the above

Question 9

The Shine-Dalgarno sequence found in prokaryotic systems resides on the ____ end of ____ and is the ____ site.

Accepted Answer

A)  3'; peptidyl-tRNA; formyl transferase 
B)  5'; DNA; polymerase binding 
C)  3'; rRNA; initiation factor binding 
D)  5'; mRNA; ribosome binding 
E)  3'; aminoacyl-tRNA; formyl methionine binding 
A)  3'; peptidyl-tRNA; formyl transferase 
B)  5'; DNA; polymerase binding 
C)  3'; rRNA; initiation factor binding 
D)  5'; mRNA; ribosome binding 
E)  3'; aminoacyl-tRNA; formyl methionine binding

Question 10

Aminoacyl-tRNA synthetases exhibit all of these characteristics EXCEPT:

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. 
E)  they must "read" the anticodon of the tRNA. 
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. 
E)  they must "read" the anticodon of the tRNA.

Question 11

____ are the agents of protein synthesis.

Accepted Answer

A)  Nuclei 
B)  Mitochondria 
C)  Chloroplasts 
D)  Ribosomes 
E)  Plasma membranes 
A)  Nuclei 
B)  Mitochondria 
C)  Chloroplasts 
D)  Ribosomes 
E)  Plasma membranes

Question 12

Which of the following does not reqire GTP hydrolysis?

Accepted Answer

A)  the formation of the initiation complex (translationally active 70 S ribosome complex). 
B)  the binding of the aminoacyl tRNA to the A site during elongation 
C)  translocation with release of the uncharged tRNA during elongation 
D)  the dissociation of release factors from the ribosome. 
E)  all of the above require GTP hydrolysis. 
A)  the formation of the initiation complex (translationally active 70 S ribosome complex). 
B)  the binding of the aminoacyl tRNA to the A site during elongation 
C)  translocation with release of the uncharged tRNA during elongation 
D)  the dissociation of release factors from the ribosome. 
E)  all of the above require GTP hydrolysis.

Question 13

Peptidyl transferase catalyzes the reaction in which the nucleophile is:

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. 
E)  electron pair on a ring N atom of the purine A2451. 
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. 
E)  electron pair on a ring N atom of the purine A2451.

Question 14

Discuss the structure of prokaryotic ribosomes.​

Accepted Answer

The E. coli ribosome is a roughly globul

Question 15

All are components required for peptide chain initiation EXCEPT:

Accepted Answer

A)  mRNA. 
B)  30S and 50S ribosomal subunits. 
C)  initiation factors. 
D)  GTP and f-Met-tRNAifMet. 
E)  all are true. 
A)  mRNA. 
B)  30S and 50S ribosomal subunits. 
C)  initiation factors. 
D)  GTP and f-Met-tRNAifMet. 
E)  all are true.

Question 16

Which of the following statements is true regarding the formylmethionine that serves as the first amino acid in bacterial protein synthesis?

Accepted Answer

A)  the formyl group is removed during protein synthesis leaving methionine as the first residue in all bacterial proteins 
B)  the tRNA that carries formylmethionine is the same tRNA for methionine 
C)  the formyl group donor is N10-formyl-tetrahydrofolate 
D)  an aminoacyl-tRNA synthetase that is specific for formylmethionine attaches formylmethionine to the tRNA 
E)  none of the above. 
A)  the formyl group is removed during protein synthesis leaving methionine as the first residue in all bacterial proteins 
B)  the tRNA that carries formylmethionine is the same tRNA for methionine 
C)  the formyl group donor is N10-formyl-tetrahydrofolate 
D)  an aminoacyl-tRNA synthetase that is specific for formylmethionine attaches formylmethionine to the tRNA 
E)  none of the above.

Question 17

Discuss the triplet codons that represent the same amino acid or chemically similar amino acids.​

Accepted Answer

​Codons representing the same amino acid

Question 18

The 30S subunit of E. coli ribosomes has all the following anatomical characteristics EXCEPT:

Accepted Answer

A)  "head". 
B)  "body" or "base". 
C)  "platform". 
D)  "legs". 
E)  all are true. 
A)  "head". 
B)  "body" or "base". 
C)  "platform". 
D)  "legs". 
E)  all are true.

Question 19

All are true for the "wobble position" EXCEPT:

Accepted Answer

A)  It is the third base of the codon. 
B)  A certain amount of play might occur in base pairing at this position. 
C)  The first-base anticodon U could recognize either an A or G in the wobble position. 
D)  The first-base anticodon G could recognize either a U or C in the wobble position. 
E)  All are true. 
A)  It is the third base of the codon. 
B)  A certain amount of play might occur in base pairing at this position. 
C)  The first-base anticodon U could recognize either an A or G in the wobble position. 
D)  The first-base anticodon G could recognize either a U or C in the wobble position. 
E)  All are true.

Question 20

Ribosomes constitute about ____ of the dry cell mass of an E. coli cell.

Accepted Answer

A)  1% 
B)  5% 
C)  10% 
D)  20% 
E)  40% 
A)  1% 
B)  5% 
C)  10% 
D)  20% 
E)  40%

Exam 30: Protein Synthesis

Termination of translation in prokaryotic cells requires:

The central domain of the ____S ribosomal subunit serves as the decoding center and is composed only of ____S rRNA.

The genetic code has all of the following characteristics EXCEPT:

All are characteristics of eukaryotic mRNA EXCEPT:

Intact 70S ribosomes are ____ in initiation of protein synthesis because ____ 30S subunits can interact with initiation factors.

Mitochondrial and chloroplastic ribosomes resemble ____ ribosomes.

Protein biosynthesis in all cells utilizes energy driving the assembly process provided by ____ hydrolysis.

The actual peptide bond-forming step in translation is referred to as ____, and is catalyzed by ____.

The Shine-Dalgarno sequence found in prokaryotic systems resides on the ____ end of ____ and is the ____ site.

Aminoacyl-tRNA synthetases exhibit all of these characteristics EXCEPT:

____ are the agents of protein synthesis.

Which of the following does not reqire GTP hydrolysis?

Peptidyl transferase catalyzes the reaction in which the nucleophile is:

Discuss the structure of prokaryotic ribosomes.​

All are components required for peptide chain initiation EXCEPT:

Which of the following statements is true regarding the formylmethionine that serves as the first amino acid in bacterial protein synthesis?

Discuss the triplet codons that represent the same amino acid or chemically similar amino acids.​

The 30S subunit of E. coli ribosomes has all the following anatomical characteristics EXCEPT:

All are true for the "wobble position" EXCEPT:

Ribosomes constitute about ____ of the dry cell mass of an E. coli cell.

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

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids and the Peptide Bond

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, Tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Membranes and Membrane Transport

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Recombinant Dna, Cloning, Chimeric Genes, and Synthetic Biology

Enzymeskinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Metabolism: an Overview

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Lipid Biosynthesis

Nitrogen Acquisition and Amino Acid Metabolism

Synthesis and Degradation of Nucleotides

Metabolic Integration and Organ Specialization

Dna Metabolism: Replication, Recombination, and Repair

Transcription and the Regulation of Gene Expression

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

The Reception and Transmission of Extracellular Information

Filters

The central domain of the S ribosomal subunit serves as the decoding center and is composed only of S rRNA.

Intact 70S ribosomes are in initiation of protein synthesis because 30S subunits can interact with initiation factors.

The actual peptide bond-forming step in translation is referred to as , and is catalyzed by .

The Shine-Dalgarno sequence found in prokaryotic systems resides on the end of and is the site.

Discuss the structure of prokaryotic ribosomes.

Discuss the triplet codons that represent the same amino acid or chemically similar amino acids.