Question 1

DNA polymerase III from E. coli

Accepted Answer

A)  is a large, multisubunit protein 
B)  has a sliding clamp portion that anchors it to DNA 
C)  has a polymerization site separate from the DNA binding site 
D)  all of these 
A)  is a large, multisubunit protein 
B)  has a sliding clamp portion that anchors it to DNA 
C)  has a polymerization site separate from the DNA binding site 
D)  all of these D

Question 2

Which of the following enzymes is used to create AP sites?

Accepted Answer

A)  primase 
B)  helicase 
C)  ligase 
D)  glycosylase 
A)  primase 
B)  helicase 
C)  ligase 
D)  glycosylase D

Question 3

The enzyme that attaches the Okazaki fragments together is called

Accepted Answer

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

Question 4

The famous Meselson and Stahl experiment showed:

Accepted Answer

A)  DNA is replicated by a semi-conservative mechanism. 
B)  The direction of DNA synthesis proceeds 5' → 3'. 
C)  The isotope 15N is denser than 14N. 
D)  DNA replication is semi-conservative and 15N is denser than 14N. 
E)  All of these are correct. 
A)  DNA is replicated by a semi-conservative mechanism. 
B)  The direction of DNA synthesis proceeds 5' → 3'. 
C)  The isotope 15N is denser than 14N. 
D)  DNA replication is semi-conservative and 15N is denser than 14N. 
E)  All of these are correct.

Question 5

DNA replication is a challenging process because:

Accepted Answer

A)  DNA strands must be separated 
B)  New DNA is always synthesized from the 5' → 3 ' direction but the two template strands run in opposite directions 
C)  The cell must guard against replication errors 
D)  All of these 
A)  DNA strands must be separated 
B)  New DNA is always synthesized from the 5' → 3 ' direction but the two template strands run in opposite directions 
C)  The cell must guard against replication errors 
D)  All of these

Question 6

At the replisome of prokaryotic replication

Accepted Answer

A)  there are only two DNA Polymerase III molecules 
B)  There are multiple copies of DNA Polymerase I 
C)  Two molecules of Polymerase III are dedicated to lagging strand synthesis while one is dedicated to leading strand synthesis 
D)  none of these 
A)  there are only two DNA Polymerase III molecules 
B)  There are multiple copies of DNA Polymerase I 
C)  Two molecules of Polymerase III are dedicated to lagging strand synthesis while one is dedicated to leading strand synthesis 
D)  none of these

Question 7

In E. coli ,

Accepted Answer

A)  the leading strand is synthesized in one piece while the lagging strand is synthesized discontinuously. 
B)  the leading strand is synthesized discontinuously while the lagging strand is synthesized in one piece. 
C)  both the leading and lagging strands are synthesized in one piece. 
D)  both the leading and lagging strands are synthesized discontinuously. 
A)  the leading strand is synthesized in one piece while the lagging strand is synthesized discontinuously. 
B)  the leading strand is synthesized discontinuously while the lagging strand is synthesized in one piece. 
C)  both the leading and lagging strands are synthesized in one piece. 
D)  both the leading and lagging strands are synthesized discontinuously.

Question 8

DNA is synthesized from the 3' end to the 5' end in which of the following processes?

Accepted Answer

A)  Replication of DNA 
B)  Replication of RNA 
C)  Transcription of RNA from DNA 
D)  none of these 
A)  Replication of DNA 
B)  Replication of RNA 
C)  Transcription of RNA from DNA 
D)  none of these

Question 9

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 10

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 11

Which of the activities of DNA Polymerase I is most important in removing the primer?

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 primer removal. 
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 primer removal.

Question 12

Ultra-violet light principally causes which of the following damages to DNA?

Accepted Answer

A)  mismatches between stands 
B)  breaks in the phosphodiester backbone of the DNA strand 
C)  thymine dimerization 
D)  methylation of specific bases 
A)  mismatches between stands 
B)  breaks in the phosphodiester backbone of the DNA strand 
C)  thymine dimerization 
D)  methylation of specific bases

Question 13

An important process in the synthesis of new DNA is

Accepted Answer

A)  proofreading and repair. 
B)  unwinding of the double helix. 
C)  protection of single-stranded regions from nuclease action. 
D)  all of these 
A)  proofreading and repair. 
B)  unwinding of the double helix. 
C)  protection of single-stranded regions from nuclease action. 
D)  all of these

Question 14

A special protein called proliferating cell nuclear antigen serves the purpose of the clamp in eukaryotes.

Accepted Answer

A) True 
 B)False

Question 15

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

Question 16

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 17

The energetic driving force for nucleic acid synthesis is

Accepted Answer

A)  removal of pyrophosphate from the incoming nucleotide. 
B)  removal of pyrophosphate from the growing strand. 
C)  removal of inorganic phosphate from the incoming nucleotide. 
D)  removal of inorganic phosphate from the growing strand. 
A)  removal of pyrophosphate from the incoming nucleotide. 
B)  removal of pyrophosphate from the growing strand. 
C)  removal of inorganic phosphate from the incoming nucleotide. 
D)  removal of inorganic phosphate from the growing strand.

Question 18

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

Question 19

Okazaki fragments are

Accepted Answer

A)  short DNA pieces that explain how DNA is synthesized on the lagging strand. 
B)  short DNA pieces that explain how DNA is synthesized on the leading strand. 
C)  the remnants of the original strands that are dispersed in the new double stranded DNA molecules 
D)  RNA primers used for DNA replication. 
A)  short DNA pieces that explain how DNA is synthesized on the lagging strand. 
B)  short DNA pieces that explain how DNA is synthesized on the leading strand. 
C)  the remnants of the original strands that are dispersed in the new double stranded DNA molecules 
D)  RNA primers used for DNA replication.

Question 20

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.

Exam 10: Biosynthesis of Nucleic Acids Replication

DNA polymerase III from E. coli

Which of the following enzymes is used to create AP sites?

The enzyme that attaches the Okazaki fragments together is called

The famous Meselson and Stahl experiment showed:

DNA replication is a challenging process because:

At the replisome of prokaryotic replication

In E. coli ,

DNA is synthesized from the 3' end to the 5' end in which of the following processes?

How do origins of replication differ in eukaryotes and prokaryotes?

Which of the following is true about clamp loaders?

Which of the activities of DNA Polymerase I is most important in removing the primer?

Ultra-violet light principally causes which of the following damages to DNA?

An important process in the synthesis of new DNA is

A special protein called proliferating cell nuclear antigen serves the purpose of the clamp in eukaryotes.

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

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

The energetic driving force for nucleic acid synthesis is

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

Okazaki fragments are

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 the 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

Filters