Question 1

HIF-1 is related to which process?

Accepted Answer

A)  How we adapt to high altitude 
B)  Pain tolerance 
C)  Transcription attenuation 
D)  all of these 
A)  How we adapt to high altitude 
B)  Pain tolerance 
C)  Transcription attenuation 
D)  all of these

Question 2

The protein which marks proteins for degradation is called:

Accepted Answer

A)  Chaperonin 
B)  Ubiquitin 
C)  Proteasomin 
D)  Apoptosin 
E)  None of these names is correct. 
A)  Chaperonin 
B)  Ubiquitin 
C)  Proteasomin 
D)  Apoptosin 
E)  None of these names is correct.

Question 3

Why do scientists believe the ribosome is a ribozyme?

Accepted Answer

A)  because there are no proteins in ribosomes 
B)  because only RNA can catalyze reactions 
C)  because protein inhibitors have no effect on ribosomes 
D)  because x-ray crystallography showed that there is no protein in the vicinity of the active site of the peptidyl transferase reaction 
A)  because there are no proteins in ribosomes 
B)  because only RNA can catalyze reactions 
C)  because protein inhibitors have no effect on ribosomes 
D)  because x-ray crystallography showed that there is no protein in the vicinity of the active site of the peptidyl transferase reaction

Question 4

The initiation of eukaryotic translation can be a control point in overall gene expression?

Accepted Answer

A) True 
 B)False

Question 5

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

Question 6

Amino acids linked to the 2'-end of a tRNA

Accepted Answer

A)  are regular substrates for protein synthesis. 
B)  are transferred to the 3' position prior to their use in protein synthesis. 
C)  are prompted hydrolysed off as part of a proofreading mechanism. 
D)  never occur. 
A)  are regular substrates for protein synthesis. 
B)  are transferred to the 3' position prior to their use in protein synthesis. 
C)  are prompted hydrolysed off as part of a proofreading mechanism. 
D)  never occur.

Question 7

Inosine or hypoxanthine can wobble with all the following bases, except:

Accepted Answer

A)  A 
B)  C 
C)  T 
D)  U 
E)  Inosine can wobble with all of these bases. 
A)  A 
B)  C 
C)  T 
D)  U 
E)  Inosine can wobble with all of these bases.

Question 8

What happens when a stop codon is reached by a ribosome (in the A site)?

Accepted Answer

A)  A termination tRNAter binds to the codon and is used to release the growing peptide from the P site tRNA. The ribosome then dissociates. 
B)  A termination tRNAter binds to the codon and the growing peptide is transferred to it. When the peptidyl-tRNAter reaches the P site, the ribosome is signaled to release the protein. The ribosome then dissociates. 
C)  A termination protein binds to the codon and is used to release the growing peptide from the P site tRNA. The ribosome then is likely to dissociate. 
D)  A termination protein binds to the codon and the ribosome dissociates. A separate peptidyl transferase then releases the protein from the last tRNA to which was attached. 
A)  A termination tRNAter binds to the codon and is used to release the growing peptide from the P site tRNA. The ribosome then dissociates. 
B)  A termination tRNAter binds to the codon and the growing peptide is transferred to it. When the peptidyl-tRNAter reaches the P site, the ribosome is signaled to release the protein. The ribosome then dissociates. 
C)  A termination protein binds to the codon and is used to release the growing peptide from the P site tRNA. The ribosome then is likely to dissociate. 
D)  A termination protein binds to the codon and the ribosome dissociates. A separate peptidyl transferase then releases the protein from the last tRNA to which was attached.

Question 9

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 10

Which amino acids have unique codons?

Accepted Answer

A)  met, gly 
B)  trp, met 
C)  tyr, met 
D)  stop, his 
A)  met, gly 
B)  trp, met 
C)  tyr, met 
D)  stop, his

Question 11

Exceptions to the universality of the genetic code have been observed in

Accepted Answer

A)  viruses 
B)  prokaryotes 
C)  eukaryotes 
D)  mitochondria and 16 other organisms, including some algae and fungae 
A)  viruses 
B)  prokaryotes 
C)  eukaryotes 
D)  mitochondria and 16 other organisms, including some algae and fungae

Question 12

The initial step in the formation of an aminoacyl-tRNA is

Accepted Answer

A)  esterification of the tRNA 
B)  activation of the amino acid by reaction with ATP 
C)  activation of the tRNA by reaction with ATP 
D)  interaction of the mRNA with the tRNA 
A)  esterification of the tRNA 
B)  activation of the amino acid by reaction with ATP 
C)  activation of the tRNA by reaction with ATP 
D)  interaction of the mRNA with the tRNA

Question 13

Which of the following is not a key advantage of wobble in the codon-anticodon reaction?

Accepted Answer

A)  It allows for fewer tRNAs in the cell. 
B)  It allows for making more than one protein from the same coding sequence. 
C)  It allows for a certain amount of mutation in the mRNA without affecting the protein sequence. 
D)  All of these are advantages of wobble. 
A)  It allows for fewer tRNAs in the cell. 
B)  It allows for making more than one protein from the same coding sequence. 
C)  It allows for a certain amount of mutation in the mRNA without affecting the protein sequence. 
D)  All of these are advantages of wobble.

Question 14

There is no codon for the amino acid hydroxyproline, but this amino acid is a prominent feature of collagen structure. Which of the following is a likely explanation?

Accepted Answer

A)  Hydroxyproline is substituted for proline after translation by a cut and patch mechanism. 
B)  Proline is covalently modified to give hydroxyproline after translation. 
C)  There is an alternative mechanism for synthesis of proteins that contain hydroxyproline. 
D)  It is not possible to form a hypothesis from the information given. 
A)  Hydroxyproline is substituted for proline after translation by a cut and patch mechanism. 
B)  Proline is covalently modified to give hydroxyproline after translation. 
C)  There is an alternative mechanism for synthesis of proteins that contain hydroxyproline. 
D)  It is not possible to form a hypothesis from the information given.

Question 15

The majority of protein synthesis occurs in the

Accepted Answer

A)  nucleus 
B)  mitochondrion 
C)  cytoplasm 
D)  nucleolus 
A)  nucleus 
B)  mitochondrion 
C)  cytoplasm 
D)  nucleolus

Question 16

At which position on the mRNA is the wobble base of the triplet codon?

Accepted Answer

A)  first position (5' letter) 
B)  second position 
C)  third position (3' letter) 
D)  the wobble base can be at any position 
A)  first position (5' letter) 
B)  second position 
C)  third position (3' letter) 
D)  the wobble base can be at any position

Question 17

What is the mode of action of puromycin in the inhibition of protein synthesis?

Accepted Answer

A)  inhibition of peptidyl transferase 
B)  inactivation of EF−G 
C)  termination of the growing polypeptide chain 
D)  dissociation of mRNA from the ribosome 
A)  inhibition of peptidyl transferase 
B)  inactivation of EF−G 
C)  termination of the growing polypeptide chain 
D)  dissociation of mRNA from the ribosome

Question 18

A tRNA was determined to have the following anticodon sequence: 3'−GAI−5' (I represents the base hypoxanthine) Which of the following codons can form base pairs with this anticodon?

Accepted Answer

A)  5'−CUA−3' 
B)  5'−CUC−3' 
C)  5'−CUU−3' 
D)  all of these 
A)  5'−CUA−3' 
B)  5'−CUC−3' 
C)  5'−CUU−3' 
D)  all of these

Question 19

How many codons are possible in a system in which a sequence of three bases specifies a single amino acid?

Accepted Answer

A)  20 
B)  24 
C)  27 
D)  64 
A)  20 
B)  24 
C)  27 
D)  64

Question 20

At which position on tRNA is the wobble base of the triplet anticodon?

Accepted Answer

A)  1st position (5' letter) 
B)  2nd position 
C)  3rd position (3' letter) 
D)  Wobble can occur at any position. 
A)  1st position (5' letter) 
B)  2nd position 
C)  3rd position (3' letter) 
D)  Wobble can occur at any position.

Exam 12: Protein Synthesis: Translation of the Genetic Message

HIF-1 is related to which process?

The protein which marks proteins for degradation is called:

Why do scientists believe the ribosome is a ribozyme?

The initiation of eukaryotic translation can be a control point in overall gene expression?

The tRNAs may bind to the standard stop codons

Amino acids linked to the 2'-end of a tRNA

Inosine or hypoxanthine can wobble with all the following bases, except:

What happens when a stop codon is reached by a ribosome (in the A site)?

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

Which amino acids have unique codons?

Exceptions to the universality of the genetic code have been observed in

The initial step in the formation of an aminoacyl-tRNA is

Which of the following is not a key advantage of wobble in the codon-anticodon reaction?

There is no codon for the amino acid hydroxyproline, but this amino acid is a prominent feature of collagen structure. Which of the following is a likely explanation?

The majority of protein synthesis occurs in the

At which position on the mRNA is the wobble base of the triplet codon?

What is the mode of action of puromycin in the inhibition of protein synthesis?

A tRNA was determined to have the following anticodon sequence: 3'−GAI−5' (I represents the base hypoxanthine) Which of the following codons can form base pairs with this anticodon?

How many codons are possible in a system in which a sequence of three bases specifies a single amino acid?

At which position on tRNA is the wobble base of the triplet anticodon?

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

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