Question 1

Which of the following play a role in DNA replication in eukaryotes?

Accepted Answer

A)  cyclin-dependent kinases 
B)  origin recognition complex 
C)  replication licensing factors 
D)  all of these 
A)  cyclin-dependent kinases 
B)  origin recognition complex 
C)  replication licensing factors 
D)  all of these D

Question 2

In the synthesis of DNA in Escherichia coli

Accepted Answer

A)  a single-strand nick in the template DNA gives rise to a swivel point just in advance of the replication fork 
B)  Mn2+ is required 
C)  all enzymes involved are single polypeptide chains 
D)  neither the template DNA nor the daughter DNA molecules exhibit supercoiling 
A)  a single-strand nick in the template DNA gives rise to a swivel point just in advance of the replication fork 
B)  Mn2+ is required 
C)  all enzymes involved are single polypeptide chains 
D)  neither the template DNA nor the daughter DNA molecules exhibit supercoiling A

Question 3

Which of the following is a characteristic of eukaryotic, but not prokaryotic, DNA replication?

Accepted Answer

A)  Topoisomerases are required. 
B)  A primer is needed on the lagging strand only. 
C)  Histone biosynthesis must take place. 
D)  There is only one origin of replication. 
A)  Topoisomerases are required. 
B)  A primer is needed on the lagging strand only. 
C)  Histone biosynthesis must take place. 
D)  There is only one origin of replication. C

Question 4

Which of the following mechanisms can serve to repair double-stranded breaks in DNA?

Accepted Answer

A)  Non-homologous end joining 
B)  recombination 
C)  base excision repair 
D)  nucleotide excision repair 
E)  both a and b 
A)  Non-homologous end joining 
B)  recombination 
C)  base excision repair 
D)  nucleotide excision repair 
E)  both a and b

Question 5

Which of the activities of DNA Polymerase I is most important in its role of proofreading?

Accepted Answer

A)  Polymerase activity. 
B)  Ability to nick intact double stranded DNA. 
C)  5' → 3' exonuclease. 
D)  3' → 5' exonuclease. 
E)  None of these is used for proofreading. 
A)  Polymerase activity. 
B)  Ability to nick intact double stranded DNA. 
C)  5' → 3' exonuclease. 
D)  3' → 5' exonuclease. 
E)  None of these is used for proofreading.

Question 6

The following enzyme is responsible for the bulk of DNA synthesis during replication.

Accepted Answer

A)  DNA Polymerase I 
B)  DNA Polymerase II 
C)  DNA Polymerase III 
D)  DNA Polymerases IV 
E)  All four can make lots of DNA rapidly. 
A)  DNA Polymerase I 
B)  DNA Polymerase II 
C)  DNA Polymerase III 
D)  DNA Polymerases IV 
E)  All four can make lots of DNA rapidly.

Question 7

Linear eukaryotic DNA molecules

Accepted Answer

A)  have many origins of synthesis, while circular bacterial DNA usually have only one. 
B)  have only one origin of synthesis, while circular bacterial DNA usually have many. 
C)  are synthesized fully conservatively, while circular bacterial DNA is synthesized semi-conservatively. 
D)  are synthesized dispersively, while circular bacterial DNA is synthesized semi-conservatively. 
A)  have many origins of synthesis, while circular bacterial DNA usually have only one. 
B)  have only one origin of synthesis, while circular bacterial DNA usually have many. 
C)  are synthesized fully conservatively, while circular bacterial DNA is synthesized semi-conservatively. 
D)  are synthesized dispersively, while circular bacterial DNA is synthesized semi-conservatively.

Question 8

The mechanism for all template-directed synthesis of any type of nucleic acid involves the following:

Accepted Answer

A)  Nucleophilic attack of a 3' hydroxyl toward a nucleoside triphosphate, releasing PPi. 
B)  Nucleophilic attack of a 5' hydroxyl toward a nucleoside triphosphate, releasing PPi. 
C)  Nucleophilic attack of a 3' hydroxyl toward a nucleoside triphosphate, releasing Pi. 
D)  Nucleophilic attack of a 5' hydroxyl toward a nucleoside triphosphate, releasing Pi. 
E)  More than one of these would work, since the mechanism is not universal. 
A)  Nucleophilic attack of a 3' hydroxyl toward a nucleoside triphosphate, releasing PPi. 
B)  Nucleophilic attack of a 5' hydroxyl toward a nucleoside triphosphate, releasing PPi. 
C)  Nucleophilic attack of a 3' hydroxyl toward a nucleoside triphosphate, releasing Pi. 
D)  Nucleophilic attack of a 5' hydroxyl toward a nucleoside triphosphate, releasing Pi. 
E)  More than one of these would work, since the mechanism is not universal.

Question 9

The replisome in prokaryotic replication consists of:

Accepted Answer

A)  a protein dimer 
B)  a protein tetramer 
C)  a multisubunit complex of at least 13 different proteins 
D)  more than 100 separate proteins 
A)  a protein dimer 
B)  a protein tetramer 
C)  a multisubunit complex of at least 13 different proteins 
D)  more than 100 separate proteins

Question 10

Telomerase activity in cancer cells may explain their longevity.

Accepted Answer

A) True 
 B)False

Question 11

Semiconservative replication implies that

Accepted Answer

A)  each of the new double stranded DNA molecules contains one of the original intact strands and one completely new strand. 
B)  one of the new double stranded DNA molecules contains both of the original strands, while the other contains two new strands. 
C)  each of the new double stranded DNA molecules contains strands that are composed of segments of original and newly synthesized material. 
D)  None of these. 
A)  each of the new double stranded DNA molecules contains one of the original intact strands and one completely new strand. 
B)  one of the new double stranded DNA molecules contains both of the original strands, while the other contains two new strands. 
C)  each of the new double stranded DNA molecules contains strands that are composed of segments of original and newly synthesized material. 
D)  None of these.

Question 12

One of the most important ways in which eukaryotic DNA differs from that of prokaryotes is

Accepted Answer

A)  prokaryotic DNA is complexed to proteins whereas eukaryotic DNA is not 
B)  eukaryotic DNA is complexed to proteins whereas prokaryotic DNA is not 
C)  DNA synthesis in eukaryotes takes place in the opposite direction from that in prokaryotes 
D)  there is no requirement for a primer in the synthesis of eukaryotic DNA 
A)  prokaryotic DNA is complexed to proteins whereas eukaryotic DNA is not 
B)  eukaryotic DNA is complexed to proteins whereas prokaryotic DNA is not 
C)  DNA synthesis in eukaryotes takes place in the opposite direction from that in prokaryotes 
D)  there is no requirement for a primer in the synthesis of eukaryotic DNA

Question 13

AZT, used in treating AIDS, is an effective inhibitor of nucleic acid synthesis because:

Accepted Answer

A)  It has a nitrogen group instead of a 3' OH. 
B)  It is a 2', 3' dideoxy compound. 
C)  It doesn't form good base pairs. 
D)  It inhibits RNA Polymerase needed to make RNA for new HIV virus particles. 
E)  More than one of these is correct. 
A)  It has a nitrogen group instead of a 3' OH. 
B)  It is a 2', 3' dideoxy compound. 
C)  It doesn't form good base pairs. 
D)  It inhibits RNA Polymerase needed to make RNA for new HIV virus particles. 
E)  More than one of these is correct.

Question 14

In Escherichia coli, the enzyme principally responsible for the synthesis of new DNA strands is

Accepted Answer

A)  DNA polymerase I 
B)  DNA polymerase III 
C)  DNA ligase 
D)  primase 
A)  DNA polymerase I 
B)  DNA polymerase III 
C)  DNA ligase 
D)  primase

Question 15

How do origins of replication differ in eukaryotes and prokaryotes?

Accepted Answer

A)  Eukaryotes have several origins, while prokaryotes typically have one. 
B)  Prokaryotes have several origins, while eukaryotes typically have one. 
C)  Only prokaryotes have origins of replication. 
D)  None of these. 
A)  Eukaryotes have several origins, while prokaryotes typically have one. 
B)  Prokaryotes have several origins, while eukaryotes typically have one. 
C)  Only prokaryotes have origins of replication. 
D)  None of these.

Question 16

The proofreading of DNA is especially good because "the identity of each base pair is checked before the enzyme moves on to the next base pair."

Accepted Answer

A) True 
 B)False

Question 17

Which of the following is true about clamp loaders?

Accepted Answer

A)  They are pentameric enzymes 
B)  They serve to open up the sliding clamp and insert the DNA 
C)  They are ATPases 
D)  All of these 
A)  They are pentameric enzymes 
B)  They serve to open up the sliding clamp and insert the DNA 
C)  They are ATPases 
D)  All of these

Question 18

Which of the following is not a function of DNA Polymerase III?

Accepted Answer

A)  Polymerization. 
B)  Ligating the final products. 
C)  Proofreading. 
D)  Clamping on to the template. 
E)  None of these are functions of DNA Polymerase III 
A)  Polymerization. 
B)  Ligating the final products. 
C)  Proofreading. 
D)  Clamping on to the template. 
E)  None of these are functions of DNA Polymerase III

Question 19

Exhibit 10A Consider the following diagrams showing a replication fork moving from left to right. The thick lines represent the template/parental strands. The 5' and 3' represent the ends of those template/parental strands.
  
-Refer to Exhibit 10A. Which diagram correctly depicts the orientation of the lagging and leading strands on the parentals?

Accepted Answer

A)  The top 
B)  The bottom 
C)  Neither is fully accurate. 
D)  Either would be accurate dependent on the organism being studied. 
A)  The top 
B)  The bottom 
C)  Neither is fully accurate. 
D)  Either would be accurate dependent on the organism being studied.

Question 20

Which of these proteins is used less for leading strand replication than for lagging strand replication?

Accepted Answer

A)  DNA polymerase 
B)  DNA-binding protein 
C)  DNA ligase 
D)  DNA gyrase 
A)  DNA polymerase 
B)  DNA-binding protein 
C)  DNA ligase 
D)  DNA gyrase

Exam 10: Biosynthesis of Nucleic Acids: Replication

Which of the following play a role in DNA replication in eukaryotes?

In the synthesis of DNA in Escherichia coli

Which of the following is a characteristic of eukaryotic, but not prokaryotic, DNA replication?

Which of the following mechanisms can serve to repair double-stranded breaks in DNA?

Which of the activities of DNA Polymerase I is most important in its role of proofreading?

The following enzyme is responsible for the bulk of DNA synthesis during replication.

Linear eukaryotic DNA molecules

The mechanism for all template-directed synthesis of any type of nucleic acid involves the following:

The replisome in prokaryotic replication consists of:

Telomerase activity in cancer cells may explain their longevity.

Semiconservative replication implies that

One of the most important ways in which eukaryotic DNA differs from that of prokaryotes is

AZT, used in treating AIDS, is an effective inhibitor of nucleic acid synthesis because:

In Escherichia coli, the enzyme principally responsible for the synthesis of new DNA strands is

How do origins of replication differ in eukaryotes and prokaryotes?

The proofreading of DNA is especially good because "the identity of each base pair is checked before the enzyme moves on to the next base pair."

Which of the following is true about clamp loaders?

Which of the following is not a function of DNA Polymerase III?

Which of these proteins is used less for leading strand replication than for lagging strand replication?

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

Transcription of the Genetic Code: Biosynthesis of RNA

Protein Synthesis: Translation of the Genetic Message

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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