Question 1

E.coli has three release factors (RF-1,2,3)involved in the termination of translation.

Accepted Answer

A) True 
 B)False

Question 2

Which statement is true about the attenuation mechanism of regulation?

Accepted Answer

A) Eukaryotes lack this mechanism because transcription and translation occur in different parts of the cell. 
B) Attenuation is the modern term for repression in prokaryotes. 
C) It is a form of regulation at the level of transcription,thereby preventing any translation. 
D) Attenuation is the most common type of regulation found in plants. 
A) Eukaryotes lack this mechanism because transcription and translation occur in different parts of the cell. 
B) Attenuation is the modern term for repression in prokaryotes. 
C) It is a form of regulation at the level of transcription,thereby preventing any translation. 
D) Attenuation is the most common type of regulation found in plants.

Question 3

Most mature mRNA transcripts contain multiple reading frames.

Accepted Answer

A) True 
 B)False

Question 4

If there is more globin than heme present in a reticulocyte,globin synthesis is stopped by

Accepted Answer

A) the activation of HCI (heme-controlled inhibitor). 
B) the inactivation of HCI. 
C) increasing heme synthesis. 
D) decreasing heme synthesis. 
E) activating eIF-2. 
A) the activation of HCI (heme-controlled inhibitor). 
B) the inactivation of HCI. 
C) increasing heme synthesis. 
D) decreasing heme synthesis. 
E) activating eIF-2.

Question 5

What is a reasonable number of nucleotides in a tRNA molecule?

Accepted Answer

A) 20 
B) 80 
C) 500 
D) 1000 
E) The number of nucleotides in tRNA molecules varies by several orders of magnitude,depending on the species. 
A) 20 
B) 80 
C) 500 
D) 1000 
E) The number of nucleotides in tRNA molecules varies by several orders of magnitude,depending on the species.

Question 6

The ribosome cannot distinguish initiator AUG codons from internal methionine AUG codons.

Accepted Answer

A) True 
 B)False

Question 7

The role of GTP in the elongation phase of protein synthesis is to supply energy for

Accepted Answer

A) peptide bond formation. 
B) formation of aminoacyl-tRNA molecules. 
C) movement of mRNA along the ribosome. 
D) changing the configuration of EF-Tu-GTP. 
E) All of the above. 
A) peptide bond formation. 
B) formation of aminoacyl-tRNA molecules. 
C) movement of mRNA along the ribosome. 
D) changing the configuration of EF-Tu-GTP. 
E) All of the above.

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

The role of GTP in the translocation step of protein synthesis is to supply energy for

Accepted Answer

A) peptide bond formation. 
B) dissociation of EF-G-GDP. 
C) movement of the peptidyl-tRNA from the P site to the A site. 
D) movement of the peptidyl-tRNA from the A site to the P site. 
E) None of the above. 
A) peptide bond formation. 
B) dissociation of EF-G-GDP. 
C) movement of the peptidyl-tRNA from the P site to the A site. 
D) movement of the peptidyl-tRNA from the A site to the P site. 
E) None of the above.

Question 10

The codon for the amino acid specified by the anticodon at the anticodon arm of tRNA is covalently linked to tRNA at the

Accepted Answer

A) variable arm. 
B) D arm. 
C) TyC arm. 
D) acceptor arm. 
A) variable arm. 
B) D arm. 
C) TyC arm. 
D) acceptor arm.

Question 11

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 12

At the ribosome,the codon and anticodon associate by ________.

Accepted Answer

A) hydrogen bonding 
B) disulfide bonds 
C) ionic attractions 
D) covalent bonding 
E) hydrophobic interactions 
A) hydrogen bonding 
B) disulfide bonds 
C) ionic attractions 
D) covalent bonding 
E) hydrophobic interactions

Question 13

________ carries the anticodon.

Accepted Answer

A) rRNA 
B) mRNA 
C) tRNA 
D) DNA 
A) rRNA 
B) mRNA 
C) tRNA 
D) DNA

Question 14

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 15

Translation begins to be terminated when

Accepted Answer

A) three release factors appear at the ribosome complex. 
B) three release factors enhance the hydrolysis of the peptide. 
C) an fMet tRNA codon is in the mRNA. 
D) a termination codon is in the mRNA. 
E) the ribosomal subunits dissociate from the mRNA. 
A) three release factors appear at the ribosome complex. 
B) three release factors enhance the hydrolysis of the peptide. 
C) an fMet tRNA codon is in the mRNA. 
D) a termination codon is in the mRNA. 
E) the ribosomal subunits dissociate from the mRNA.

Question 16

The ordering of amino acids to form the sequence of a protein represents a significant gain of entropy.

Accepted Answer

A) True 
 B)False

Question 17

Which help cells avoid mis-insertion of amino acids in protein synthesis?

Accepted Answer

A) The specificity of codon:anticodon interactions. 
B) The specificity of tRNA: amino acid pairs. 
C) The proofreading ability of tRNA synthetases. 
D) All of the above. 
A) The specificity of codon:anticodon interactions. 
B) The specificity of tRNA: amino acid pairs. 
C) The proofreading ability of tRNA synthetases. 
D) All of the above.

Question 18

Proteins processed through the Golgi apparatus and usually destined for export from the cell are modified by glycosylation only.

Accepted Answer

A) True 
 B)False

Question 19

How many GTP are hydrolyzed for every aminoacyl-tRNA that is successfully inserted into the A site of the ribosome?

Accepted Answer

A) zero 
B) 1 
C) 2 
D) 4 
A) zero 
B) 1 
C) 2 
D) 4

Question 20

The gene for inhibiting ribosomal protein synthesis lies within the operon for the ribosomal proteins.

Accepted Answer

A) True 
 B)False

Exam 22: Protein Synthesis

E.coli has three release factors (RF-1,2,3)involved in the termination of translation.

Which statement is true about the attenuation mechanism of regulation?

Most mature mRNA transcripts contain multiple reading frames.

If there is more globin than heme present in a reticulocyte,globin synthesis is stopped by

What is a reasonable number of nucleotides in a tRNA molecule?

The ribosome cannot distinguish initiator AUG codons from internal methionine AUG codons.

The role of GTP in the elongation phase of protein synthesis is to supply energy for

Shifting of the reading frame by one nucleotide results in ________.

The role of GTP in the translocation step of protein synthesis is to supply energy for

The codon for the amino acid specified by the anticodon at the anticodon arm of tRNA is covalently linked to tRNA at the

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

At the ribosome,the codon and anticodon associate by ________.

________ carries the anticodon.

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

Translation begins to be terminated when

The ordering of amino acids to form the sequence of a protein represents a significant gain of entropy.

Which help cells avoid mis-insertion of amino acids in protein synthesis?

Proteins processed through the Golgi apparatus and usually destined for export from the cell are modified by glycosylation only.

How many GTP are hydrolyzed for every aminoacyl-tRNA that is successfully inserted into the A site of the ribosome?

The gene for inhibiting ribosomal protein synthesis lies within the operon for the ribosomal proteins.

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 Atp Synthesis

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Filters