Question 1

Formation of disulfide bonds,phosphorylation,acetylation and removal of N-terminal residues are all examples of

Accepted Answer

A) pretranslational modifications. 
B) cotranslational modifications. 
C) posttranslational modifications. 
D) Both B and C above. 
A) pretranslational modifications. 
B) cotranslational modifications. 
C) posttranslational modifications. 
D) Both B and C above. D

Question 2

Isoacceptor tRNAs can only differ in primary sequence at the anticodon.

Accepted Answer

A) True 
 B)False  False

Question 3

Cells use a large fraction of their ATP equivalents to provide energy for protein synthesis.

Accepted Answer

A) True 
 B)False  True

Question 4

During protein synthesis the peptide bond is formed by

Accepted Answer

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

Question 5

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

Accepted Answer

A) True 
 B)False

Question 6

Amino acids are attached to tRNA at the ________.

Accepted Answer

A) anticodon region 
B) 5' end 
C) 3' end 
D) variable arm 
A) anticodon region 
B) 5' end 
C) 3' end 
D) variable arm

Question 7

Which statement is false about the energy changes during the course of protein synthesis?

Accepted Answer

A) Breakage of phosphoanhydride bonds releases energy. 
B) Conformational changes in the translational machinery consume energy. 
C) Conversion of nucleotide triphosphates to nucleotide mono- or diphosphates releases energy. 
D) The loss of entropy due to the ordering of amino acids to form a protein releases energy. 
E) None of the above statements is false.They are all true. 
A) Breakage of phosphoanhydride bonds releases energy. 
B) Conformational changes in the translational machinery consume energy. 
C) Conversion of nucleotide triphosphates to nucleotide mono- or diphosphates releases energy. 
D) The loss of entropy due to the ordering of amino acids to form a protein releases energy. 
E) None of the above statements is false.They are all true.

Question 8

What statement is not true about the Shine-Dalgarno sequence?

Accepted Answer

A) It is a pyrimidine-rich region of mRNA. 
B) It is present only in prokaryotes. 
C) It is complementary to a sequence of an rRNA sequence. 
D) It helps position the initiation codon at the P site on the ribosome. 
A) It is a pyrimidine-rich region of mRNA. 
B) It is present only in prokaryotes. 
C) It is complementary to a sequence of an rRNA sequence. 
D) It helps position the initiation codon at the P site on the ribosome.

Question 9

Release factors fit into the A site when one of three codons (UGA,UAG,or UAA)is positioned there.

Accepted Answer

A) True 
 B)False

Question 10

After proteins emerge from the ribosome,the N-terminal end starts to fold even before the entire protein is made.

Accepted Answer

A) True 
 B)False

Question 11

Which statement is false about polysomes?

Accepted Answer

A) They consist of mRNA and many translation complexes that are separated by about 100 nucleotides. 
B) They serve to amplify the information contained in mRNA many-fold. 
C) The number of translation complexes one contains depends on the efficiency of initiation. 
D) They do not occur in prokaryotes. 
A) They consist of mRNA and many translation complexes that are separated by about 100 nucleotides. 
B) They serve to amplify the information contained in mRNA many-fold. 
C) The number of translation complexes one contains depends on the efficiency of initiation. 
D) They do not occur in prokaryotes.

Question 12

The role of EF-Tu in bacterial protein synthesis is

Accepted Answer

A) formation of the peptide bond. 
B) positioning the correct aminoacyl-tRNA at the A site. 
C) positioning the correct aminoacyl-tRNA at the P site. 
D) moving the mRNA by one codon. 
E) All of the above. 
A) formation of the peptide bond. 
B) positioning the correct aminoacyl-tRNA at the A site. 
C) positioning the correct aminoacyl-tRNA at the P site. 
D) moving the mRNA by one codon. 
E) All of the above.

Question 13

In prokaryotes the codons can be arranged in an overlapping fashion.In eukaryotes they are arranged only in a non-overlapping fashion.

Accepted Answer

A) True 
 B)False

Question 14

The unambiguity and degeneracy of the genetic code can best be respectively exemplified by which of the following?

Accepted Answer

A) UUU and UUC both code for Phe;UUU codes only for Phe. 
B) UUU codes only for Phe;UUU and UUC both code for Phe. 
C) UUU codes for both Phe and Ser;UUU and UUC both code for Phe and Ser. 
D) UUU and UUC both code for Phe and Ser;UUU codes for both Phe and Ser. 
A) UUU and UUC both code for Phe;UUU codes only for Phe. 
B) UUU codes only for Phe;UUU and UUC both code for Phe. 
C) UUU codes for both Phe and Ser;UUU and UUC both code for Phe and Ser. 
D) UUU and UUC both code for Phe and Ser;UUU codes for both Phe and Ser.

Question 15

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

Accepted Answer

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

Question 16

Puromycin can be used clinically because it inhibits bacterial protein synthesis by resembling aminoacyl-tRNA.

Accepted Answer

A) True 
 B)False

Question 17

In eukaryotes what is the function of eIF-4 (cap binding protein)?

Accepted Answer

A) It assists in the dissociation of the ribosomal complex following termination of translation. 
B) It cleaves the first amino acid on a newly translated protein. 
C) It binds to the 5' end of mRNA and assists in the formation of the pre-initiation complex. 
D) It acts as a general acid-base catalyst during the formation of the peptide bond. 
A) It assists in the dissociation of the ribosomal complex following termination of translation. 
B) It cleaves the first amino acid on a newly translated protein. 
C) It binds to the 5' end of mRNA and assists in the formation of the pre-initiation complex. 
D) It acts as a general acid-base catalyst during the formation of the peptide bond.

Question 18

When an oligosaccharide is covalently bonded to an asparagine (or other amino acid)side chain,the resulting product is a(n)

Accepted Answer

A) protein glycoside. 
B) glyocophorin. 
C) glycoprotein. 
D) oligoprotein. 
A) protein glycoside. 
B) glyocophorin. 
C) glycoprotein. 
D) oligoprotein.

Question 19

The E site on the ribosome is the location of

Accepted Answer

A) EF factors. 
B) a tunnel in the ribosome. 
C) the deaminoacylated tRNA. 
D) the aminoacylated tRNA. 
E) None of the above. 
A) EF factors. 
B) a tunnel in the ribosome. 
C) the deaminoacylated tRNA. 
D) the aminoacylated tRNA. 
E) None of the above.

Question 20

The acceptor stem of tRNA consists of the ________.

Accepted Answer

A) loop that includes the anticodon 
B) terminal CCA only 
C) 5' end and a region near the end 3' end that are base-paired to each other 
D) variable arm and the D arm 
A) loop that includes the anticodon 
B) terminal CCA only 
C) 5' end and a region near the end 3' end that are base-paired to each other 
D) variable arm and the D arm

Exam 22: Protein Synthesis

Formation of disulfide bonds,phosphorylation,acetylation and removal of N-terminal residues are all examples of

Isoacceptor tRNAs can only differ in primary sequence at the anticodon.

Cells use a large fraction of their ATP equivalents to provide energy for protein synthesis.

During protein synthesis the peptide bond is formed by

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

Amino acids are attached to tRNA at the ________.

Which statement is false about the energy changes during the course of protein synthesis?

What statement is not true about the Shine-Dalgarno sequence?

Release factors fit into the A site when one of three codons (UGA,UAG,or UAA)is positioned there.

After proteins emerge from the ribosome,the N-terminal end starts to fold even before the entire protein is made.

Which statement is false about polysomes?

The role of EF-Tu in bacterial protein synthesis is

In prokaryotes the codons can be arranged in an overlapping fashion.In eukaryotes they are arranged only in a non-overlapping fashion.

The unambiguity and degeneracy of the genetic code can best be respectively exemplified by which of the following?

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

Puromycin can be used clinically because it inhibits bacterial protein synthesis by resembling aminoacyl-tRNA.

In eukaryotes what is the function of eIF-4 (cap binding protein)?

When an oligosaccharide is covalently bonded to an asparagine (or other amino acid)side chain,the resulting product is a(n)

The E site on the ribosome is the location of

The acceptor stem of tRNA consists of the ________.

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

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