Question 1

At the end of the initiation step, the ribosome has a vacant

Accepted Answer

A)  A site. 
B)  P site. 
C)  mRNA site. 
D)  tRNA. 
E)  All of the above 
A)  A site. 
B)  P site. 
C)  mRNA site. 
D)  tRNA. 
E)  All of the above

Question 2

Which of the following is mismatched?

Accepted Answer

A)  initiator tRNA - recognizes AUG codons during initiation at the P site 
B)  Shine-Dalgarno sequence - upstream of the initator codon and plays a role in initiation 
C)  Shine-Dalgarno sequence - pyrimidine-rich stretch at the 3ʹ end of 16S rRNA 
D)  eukaryotic initiation factors - IF-1, IF-2, IF-3 
A)  initiator tRNA - recognizes AUG codons during initiation at the P site 
B)  Shine-Dalgarno sequence - upstream of the initator codon and plays a role in initiation 
C)  Shine-Dalgarno sequence - pyrimidine-rich stretch at the 3ʹ end of 16S rRNA 
D)  eukaryotic initiation factors - IF-1, IF-2, IF-3

Question 3

Of all the possible triplet codons, do not code for an amino acid.

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  3 
E)  4 
A)  0 
B)  1 
C)  2 
D)  3 
E)  4

Question 4

After the action of peptidyl transferase, the peptidyl-tRNA is located at the

Accepted Answer

A)  P site. 
B)  A site. 
C)  E site. 
D)  partly in the A site and partly in the P site. 
A)  P site. 
B)  A site. 
C)  E site. 
D)  partly in the A site and partly in the P site.

Question 5

Tryptophan synthesis is controlled by a repressor protein which is activated by a corepressor which is

Accepted Answer

A)  leader peptide. 
B)  promoter locus. 
C)  operator locus. 
D)  tryptophan. 
A)  leader peptide. 
B)  promoter locus. 
C)  operator locus. 
D)  tryptophan.

Question 6

How many possible codons of normal size) are possible using the bases found in DNA?

Accepted Answer

A)  4 
B)  16 
C)  20 
D)  64 
A)  4 
B)  16 
C)  20 
D)  64

Question 7

The EF-Tu-GTP complex recognizes fMet-tRNAfmet in bacteria but not in eukaryotic cells.

Accepted Answer

A) True 
 B)False

Question 8

Shifting of the reading frame by one nucleotide results in .

Accepted Answer

A)  the production of a completely different protein that is likely non-functional 
B)  a substitution only at the first amino acid 
C)  the generation of homologous proteins 
D)  a protein that has one less or one more amino acid 
A)  the production of a completely different protein that is likely non-functional 
B)  a substitution only at the first amino acid 
C)  the generation of homologous proteins 
D)  a protein that has one less or one more amino acid

Question 9

At the ribosome the template mRNA is translated in the direction, while the protein is synthesized in the direction.

Accepted Answer

A)  5ʹ → 3ʹ; N-terminal to C-terminal 
B)  5ʹ → 3ʹ; C-terminal to N-terminal 
C)  3ʹ → 5ʹ; N-terminal to C-terminal 
D)  3ʹ → 5ʹ; C-terminal to N-terminal 
A)  5ʹ → 3ʹ; N-terminal to C-terminal 
B)  5ʹ → 3ʹ; C-terminal to N-terminal 
C)  3ʹ → 5ʹ; N-terminal to C-terminal 
D)  3ʹ → 5ʹ; C-terminal to N-terminal

Question 10

Prokaryotic mRNA molecules that contain several coding regions that encode several polypeptides are .

Accepted Answer

A)  synonymous 
B)  tandemly coded 
C)  polycistronic 
D)  impossible 
A)  synonymous 
B)  tandemly coded 
C)  polycistronic 
D)  impossible

Question 11

Puromycin is an antibiotic that inhibits protein synthesis because

Accepted Answer

A)  it binds a ribosomal protein. 
B)  it inhibits peptidyl transferase. 
C)  it binds to the 50S subunit preventing translocation. 
D)  it looks like aminoacyl-tRNA and binds to the A site. 
E)  it binds to the E site. 
A)  it binds a ribosomal protein. 
B)  it inhibits peptidyl transferase. 
C)  it binds to the 50S subunit preventing translocation. 
D)  it looks like aminoacyl-tRNA and binds to the A site. 
E)  it binds to the E site.

Question 12

Arrange the events listed below in order according to the signal hypothesis: I. Signal sequence binds to SRP
II. Translation stops
III. Translation starts
IV. Ribophorins anchor complex
V. SRP dissociates; GTP hydrolyzed
VI. SRP-signal complex binds to docking protein

Accepted Answer

A)  I → II → II → IV → V → VI 
B)  I → III → VI → V → II → IV 
C)  V → III → IV → VI → II → I 
D)  I → II → VI → IV → III → V 
A)  I → II → II → IV → V → VI 
B)  I → III → VI → V → II → IV 
C)  V → III → IV → VI → II → I 
D)  I → II → VI → IV → III → V

Question 13

The correct order for the formation of the prokaryotic 70S initiation complex is

Accepted Answer

A)  50S → IF-1, IF-2 → mRNA → fMet-tRNAfmet → 30S 
B)  30S → IF-1, IF-3 → fMet-tRNAfmet → IF-2 → mRNA → 50S 
C)  30S → IF-1, IF-3 → IF-2 → fMet-tRNAfmet → mRNA → 50S 
D)  30S → IF-1, IF-2 → IF-3 → fMet-tRNAfmet → mRNA → 50S 
A)  50S → IF-1, IF-2 → mRNA → fMet-tRNAfmet → 30S 
B)  30S → IF-1, IF-3 → fMet-tRNAfmet → IF-2 → mRNA → 50S 
C)  30S → IF-1, IF-3 → IF-2 → fMet-tRNAfmet → mRNA → 50S 
D)  30S → IF-1, IF-2 → IF-3 → fMet-tRNAfmet → mRNA → 50S

Question 14

At the beginning of translocation, the growing peptide chain is attached to tRNA located at the on the ribosome.

Accepted Answer

A)  P site and part of the A site 
B)  A site and part of the P site 
C)  A site only 
D)  P site only 
A)  P site and part of the A site 
B)  A site and part of the P site 
C)  A site only 
D)  P site only

Question 15

The peptide bond is formed by

Accepted Answer

A)  a protein-catalyzed reaction. 
B)  an RNA-catalyzed reaction. 
C)  a combination of A and B. 
D)  hydrolysis of ATP. 
E)  hydrolysis of CTP. 
A)  a protein-catalyzed reaction. 
B)  an RNA-catalyzed reaction. 
C)  a combination of A and B. 
D)  hydrolysis of ATP. 
E)  hydrolysis of CTP.

Question 16

There are five times more ribosomes in eukaryotic cells than in most bacterial cells.

Accepted Answer

A) True 
 B)False

Question 17

Tryptophan synthesis can be controlled by controlling transcription but not translation.

Accepted Answer

A) True 
 B)False

Question 18

The initiation codon .

Accepted Answer

A)  specifies uracil 
B)  specifies methionine 
C)  binds a protein complex that starts translation 
D)  is part of the TATA box 
A)  specifies uracil 
B)  specifies methionine 
C)  binds a protein complex that starts translation 
D)  is part of the TATA box

Question 19

The first amino acid incorporated into proteins .

Accepted Answer

A)  can be any of the 20 standard amino acids 
B)  is an N-formylmethionine in E. coli and methionine in other organisms 
C)  is always inosinate 
D)  is an amidated methionine residue that is cleaved following termination of translation 
A)  can be any of the 20 standard amino acids 
B)  is an N-formylmethionine in E. coli and methionine in other organisms 
C)  is always inosinate 
D)  is an amidated methionine residue that is cleaved following termination of translation

Question 20

Most mature mRNA transcripts contain multiple reading frames.

Accepted Answer

A) True 
 B)False

Exam 22: Protein Synthesis

At the end of the initiation step, the ribosome has a vacant

Which of the following is mismatched?

Of all the possible triplet codons, do not code for an amino acid.

After the action of peptidyl transferase, the peptidyl-tRNA is located at the

Tryptophan synthesis is controlled by a repressor protein which is activated by a corepressor which is

How many possible codons of normal size) are possible using the bases found in DNA?

The EF-Tu-GTP complex recognizes fMet-tRNAfmet in bacteria but not in eukaryotic cells.

Shifting of the reading frame by one nucleotide results in .

At the ribosome the template mRNA is translated in the direction, while the protein is synthesized in the direction.

Prokaryotic mRNA molecules that contain several coding regions that encode several polypeptides are .

Puromycin is an antibiotic that inhibits protein synthesis because

Arrange the events listed below in order according to the signal hypothesis: I. Signal sequence binds to SRP II. Translation stops III. Translation starts IV. Ribophorins anchor complex V. SRP dissociates; GTP hydrolyzed VI. SRP-signal complex binds to docking protein

The correct order for the formation of the prokaryotic 70S initiation complex is

At the beginning of translocation, the growing peptide chain is attached to tRNA located at the on the ribosome.

The peptide bond is formed by

There are five times more ribosomes in eukaryotic cells than in most bacterial cells.

Tryptophan synthesis can be controlled by controlling transcription but not translation.

The initiation codon .

The first amino acid incorporated into proteins .

Most mature mRNA transcripts contain multiple reading frames.

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

Dna Replication, Repair, and Recombination

Transcription and Rna Processing

Recombinant Dna Technology

Filters

The EF-Tu-GTP complex recognizes fMet-tRNA_f^metin bacteria but not in eukaryotic cells.