Question 1

Protein synthesis in prokaryotes always starts with

Accepted Answer

A)  a methionine residue 
B)  a formylmethionine residue 
C)  a cysteine residue 
D)  no specific residue 
A)  a methionine residue 
B)  a formylmethionine residue 
C)  a cysteine residue 
D)  no specific residue B

Question 2

The tRNAs may bind to the standard stop codons

Accepted Answer

A)  in cellular organelles which use a modified genetic code. 
B)  to accommodate the tRNA for the unusual amino acid selenocysteine. 
C)  when the anticodon in a tRNA mutates to a sequence which can bind. 
D)  All of these 
A)  in cellular organelles which use a modified genetic code. 
B)  to accommodate the tRNA for the unusual amino acid selenocysteine. 
C)  when the anticodon in a tRNA mutates to a sequence which can bind. 
D)  All of these D

Question 3

The standard free energy change for the following reaction is about zero. amino acid + ATP + tRNA aminoacyl-tRNA + AMP + PPi

The driving force for this reaction in the cell is

Accepted Answer

A)  the relatively low concentrations of the reactants 
B)  the subsequent reaction of peptide bond formation is energetically favorable 
C)  the subsequent hydrolysis of pyrophosphate releases energy 
D)  the increased resonance stability of the acyl group on aminoacyl-tRNA 
A)  the relatively low concentrations of the reactants 
B)  the subsequent reaction of peptide bond formation is energetically favorable 
C)  the subsequent hydrolysis of pyrophosphate releases energy 
D)  the increased resonance stability of the acyl group on aminoacyl-tRNA C

Question 4

The genetic code is said to be degenerate.This means that

Accepted Answer

A)  each codon codes for more than one amino acid. 
B)  each anticodon can interact with many different triplet sequences in the mRNA, which may differ in any or all of the three nucleotides. 
C)  many of the amino acids are coded for by different codons. 
D)  the code is universally used by virtually all species. 
A)  each codon codes for more than one amino acid. 
B)  each anticodon can interact with many different triplet sequences in the mRNA, which may differ in any or all of the three nucleotides. 
C)  many of the amino acids are coded for by different codons. 
D)  the code is universally used by virtually all species.

Question 5

Leader sequences for protein transport to specific organelles are removed by proteases associated with the:

Accepted Answer

A)  endoplasmic reticulum 
B)  golgi apparatus 
C)  nucleus 
D)  mitochondra 
E)  none of these 
A)  endoplasmic reticulum 
B)  golgi apparatus 
C)  nucleus 
D)  mitochondra 
E)  none of these

Question 6

The final form of mRNA in eukaryotes has all these features,except:

Accepted Answer

A)  There will be a special nucleotide cap on the 5' end of the mRNA. 
B)  There is usually a poly A tail on the 3' end of the mRNA. 
C)  The mature, active mRNA contains introns. 
D)  Only a single protein is made from any mature mRNA molecule. 
E)  All of these are true. 
A)  There will be a special nucleotide cap on the 5' end of the mRNA. 
B)  There is usually a poly A tail on the 3' end of the mRNA. 
C)  The mature, active mRNA contains introns. 
D)  Only a single protein is made from any mature mRNA molecule. 
E)  All of these are true.

Question 7

In the wobble phenomenon,the base that wobbles is found in

Accepted Answer

A)  the tRNA. 
B)  the mRNA 
C)  either the tRNA or the mRNA. 
A)  the tRNA. 
B)  the mRNA 
C)  either the tRNA or the mRNA.

Question 8

The formylation of methionine in prokaryotes

Accepted Answer

A)  depends on two different tRNAs, where methionine can be formylated when bound to one form and not the other. 
B)  depends on two different tRNAs, where methionine can be formylated when bound to either one. 
C)  depends on one tRNA, where methionine is formylated after binding. 
D)  takes place before methionine is bound to tRNA. 
A)  depends on two different tRNAs, where methionine can be formylated when bound to one form and not the other. 
B)  depends on two different tRNAs, where methionine can be formylated when bound to either one. 
C)  depends on one tRNA, where methionine is formylated after binding. 
D)  takes place before methionine is bound to tRNA.

Question 9

How do eukaryotic and prokaryotic translation compare?

Accepted Answer

A)  There is little to no difference between them; all the factors are homologous. 
B)  Eukaryotes utilize very different protein factors during the process but the ribosomes are homologous. 
C)  Eukaryotic ribosomes are very different, but the protein factors used during the process are homologous. 
D)  Both eukaryotic ribosomes and the protein factors used during the process are very different. 
A)  There is little to no difference between them; all the factors are homologous. 
B)  Eukaryotes utilize very different protein factors during the process but the ribosomes are homologous. 
C)  Eukaryotic ribosomes are very different, but the protein factors used during the process are homologous. 
D)  Both eukaryotic ribosomes and the protein factors used during the process are very different.

Question 10

During elongation,tRNA binds initially to the

Accepted Answer

A)  "A" site on the ribosome. 
B)  "P" site on the ribosome. 
C)  "E" site on the ribosome. 
A)  "A" site on the ribosome. 
B)  "P" site on the ribosome. 
C)  "E" site on the ribosome.

Question 11

Which of the following is not required for the elongation phase of protein synthesis?

Accepted Answer

A)  GTP 
B)  fmet-tRNAfmet 
C)  peptidyl transferase 
D)  mRNA 
A)  GTP 
B)  fmet-tRNAfmet 
C)  peptidyl transferase 
D)  mRNA

Question 12

Under certain conditions,tRNAs can bind to the standard stop codons.

Accepted Answer

A) True 
 B)False

Question 13

Using the genetic code,indicate which polypeptides would be synthesized if poly (UGG) were used as a synthetic mRNA?

Accepted Answer

A)  poly(gly) 
B)  poly(trp) 
C)  poly(trp-val-gly) 
D)  poly(trp), poly(val), poly(gly) 
A)  poly(gly) 
B)  poly(trp) 
C)  poly(trp-val-gly) 
D)  poly(trp), poly(val), poly(gly)

Question 14

A polysome is

Accepted Answer

A)  a complex consisting of one mRNA to which several ribosomes are attached 
B)  a polypeptide chain in the process of being formed 
C)  an intermediate stage in the self-assembly of ribosomes 
D)  an aggregate of ribosomal proteins 
A)  a complex consisting of one mRNA to which several ribosomes are attached 
B)  a polypeptide chain in the process of being formed 
C)  an intermediate stage in the self-assembly of ribosomes 
D)  an aggregate of ribosomal proteins

Question 15

Wobble allows each codon to interact with more than one tRNA.

Accepted Answer

A) True 
 B)False

Question 16

What is the start codon on the mRNA for prokaryotic translation?

Accepted Answer

A)  AUG 
B)  UAA 
C)  UAG 
D)  UGA 
A)  AUG 
B)  UAA 
C)  UAG 
D)  UGA

Question 17

An aminoacyl-adenylate contains

Accepted Answer

A)  an ester bond 
B)  an acid anhydride bond 
C)  an amide bond 
D)  an ether bond 
A)  an ester bond 
B)  an acid anhydride bond 
C)  an amide bond 
D)  an ether bond

Question 18

In bacteria,translation of the mRNA begins

Accepted Answer

A)  during the synthesis of the mRNA. 
B)  after synthesis of the mRNA has been completed. 
C)  after 5' capping of the mRNA. 
D)  after all processing (capping, polyadenylation, and removal of introns) has taken place. 
A)  during the synthesis of the mRNA. 
B)  after synthesis of the mRNA has been completed. 
C)  after 5' capping of the mRNA. 
D)  after all processing (capping, polyadenylation, and removal of introns) has taken place.

Question 19

The process of amino acid activation

Accepted Answer

A)  involves the formation of a peptide bond between the amino acid and tRNA 
B)  takes place by formation of a mixed anhydride of the amino acid and tRNA 
C)  involves the formation of an ester bond between the amino acid and tRNA 
D)  none of these 
A)  involves the formation of a peptide bond between the amino acid and tRNA 
B)  takes place by formation of a mixed anhydride of the amino acid and tRNA 
C)  involves the formation of an ester bond between the amino acid and tRNA 
D)  none of these

Question 20

Degradation of proteins

Accepted Answer

A)  happens randomly 
B)  frequently makes use of proteasomes 
C)  always requires ubiquitinylation of proteins to be degraded 
D)  tends to target proteins with basic amino acid residues at their N-terminal ends 
A)  happens randomly 
B)  frequently makes use of proteasomes 
C)  always requires ubiquitinylation of proteins to be degraded 
D)  tends to target proteins with basic amino acid residues at their N-terminal ends

Exam 12: Protein Synthesis: Translation of the Genetic Message

Protein synthesis in prokaryotes always starts with

The tRNAs may bind to the standard stop codons

The standard free energy change for the following reaction is about zero. amino acid + ATP + tRNA aminoacyl-tRNA + AMP + PPi The driving force for this reaction in the cell is

The genetic code is said to be degenerate.This means that

Leader sequences for protein transport to specific organelles are removed by proteases associated with the:

The final form of mRNA in eukaryotes has all these features,except:

In the wobble phenomenon,the base that wobbles is found in

The formylation of methionine in prokaryotes

How do eukaryotic and prokaryotic translation compare?

During elongation,tRNA binds initially to the

Which of the following is not required for the elongation phase of protein synthesis?

Under certain conditions,tRNAs can bind to the standard stop codons.

Using the genetic code,indicate which polypeptides would be synthesized if poly (UGG) were used as a synthetic mRNA?

A polysome is

Wobble allows each codon to interact with more than one tRNA.

What is the start codon on the mRNA for prokaryotic translation?

An aminoacyl-adenylate contains

In bacteria,translation of the mRNA begins

The process of amino acid activation

Degradation of proteins

Biochemistry and the Organization of Cells

Water: The Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three-Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins: Enzymes

The Behavior of Proteins: Enzymes, Mechanisms, and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids: How Structure Conveys Information

Biosynthesis of Nucleic Acids: Replication

Transcription of the Genetic Code: Biosynthesis of Rna

Nucleic Acid Biotechnology Techniques

Viruses, Cancer, and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

Filters

The standard free energy change for the following reaction is about zero. amino acid + ATP + tRNA aminoacyl-tRNA + AMP + PP_i The driving force for this reaction in the cell is