Question 1

DNA repair mechanisms are essentially the same whether the DNA has minor damage or major damage.

Accepted Answer

A) True 
 B)False

Question 2

In the original Central Dogma of biology,the ordinary flow of genetic information is:

Accepted Answer

A)  DNA RNA Protein 
B)  RNA DNA Protein 
C)  Protein RNA DNA 
D)  DNA Protein RNA. 
E)  None of these 
A)  DNA RNA Protein 
B)  RNA DNA Protein 
C)  Protein RNA DNA 
D)  DNA Protein RNA. 
E)  None of these

Question 3

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 4

Single strand binding proteins are important for this activity:

Accepted Answer

A)  Prevent single-stranded DNA from rewinding. 
B)  Protect single-stranded DNA from enzymatic degradation. 
C)  Prevent double helical DNA from unwinding. 
D)  Prevent double helical DNA from becoming a triple helix. 
E)  Prevent single-stranded DNA from rewinding and protect it from degradation. 
A)  Prevent single-stranded DNA from rewinding. 
B)  Protect single-stranded DNA from enzymatic degradation. 
C)  Prevent double helical DNA from unwinding. 
D)  Prevent double helical DNA from becoming a triple helix. 
E)  Prevent single-stranded DNA from rewinding and protect it from degradation.

Question 5

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 6

Why is thymine used in DNA rather than uracil?

Accepted Answer

A)  Thymine is more hydrophobic, so it stacks better in the helix. 
B)  If cytosine is deaminated, it forms uracil, which can be easily distinguished from thymine. 
C)  Thymine is not capable of wobbling, so it pairs more accurately than uracil. 
D)  All of these are correct. 
A)  Thymine is more hydrophobic, so it stacks better in the helix. 
B)  If cytosine is deaminated, it forms uracil, which can be easily distinguished from thymine. 
C)  Thymine is not capable of wobbling, so it pairs more accurately than uracil. 
D)  All of these are correct.

Question 7

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 8

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 9

One of the most important ways in which DNA is modified after synthesis is

Accepted Answer

A)  methylation of bases 
B)  covalent binding of proteins to the sugar moieties 
C)  splicing of RNA "leaders" 
D)  electrostatic binding of negatively charged counterions 
A)  methylation of bases 
B)  covalent binding of proteins to the sugar moieties 
C)  splicing of RNA "leaders" 
D)  electrostatic binding of negatively charged counterions

Question 10

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

Question 11

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 12

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 13

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 14

A prokaryotic replisome typically contains two molecules of DNA pol III,but only one molecule of DNA pol I.Why?

Accepted Answer

A)  The DNA pol I works on the leading strand, while DNA pol IIIs work on the Okazaki fragments. since there are several of those, it takes more proteins to keep up. 
B)  DNA pol I has a built-in proofreading exonuclease; DNA pol III does not. The second DNA pol III is needed to follow the first to accomplish the necessary proofreading. 
C)  The DNA pol IIIs do most of the work. DNA pol I only has to work on the telomers. 
D)  DNA pol I replaces the RNA primers with DNA, which really only needs to be done repetitively on one strand, while both strands are worked on by the DNA pol IIIs. 
A)  The DNA pol I works on the leading strand, while DNA pol IIIs work on the Okazaki fragments. since there are several of those, it takes more proteins to keep up. 
B)  DNA pol I has a built-in proofreading exonuclease; DNA pol III does not. The second DNA pol III is needed to follow the first to accomplish the necessary proofreading. 
C)  The DNA pol IIIs do most of the work. DNA pol I only has to work on the telomers. 
D)  DNA pol I replaces the RNA primers with DNA, which really only needs to be done repetitively on one strand, while both strands are worked on by the DNA pol IIIs.

Question 15

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

Question 16

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 17

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 18

Which of the following is not an activity of DNA Polymerase I?

Accepted Answer

A)  Polymerase activity. 
B)  Ability to nick intact double stranded DNA. 
C)  5' 3' exonuclease. 
D)  3' 5' exonuclease. 
E)  All of these are present in DNA Pol I. 
A)  Polymerase activity. 
B)  Ability to nick intact double stranded DNA. 
C)  5' 3' exonuclease. 
D)  3' 5' exonuclease. 
E)  All of these are present in DNA Pol I.

Question 19

When the synthesis of new DNA is directed by an original template DNA molecule

Accepted Answer

A)  the DNA produced has two newly formed strands (no change in the original DN
A)  
B)  two DNA molecules are formed, each with one new strand and one strand from the original DNA 
C)  there is random arrangement of newly formed and original DNA on the two strands of the DNA produced 
D)  no information is available on this subject 
A)  the DNA produced has two newly formed strands (no change in the original DN
A)  
B)  two DNA molecules are formed, each with one new strand and one strand from the original DNA 
C)  there is random arrangement of newly formed and original DNA on the two strands of the DNA produced 
D)  no information is available on this subject

Question 20

Eukaryotes need more types of DNA polymerases than bacteria because

Accepted Answer

A)  the DNA-containing organelles have their own DNA polymerases. 
B)  they have linear DNA , which is harder to replicate than circular DNA. 
C)  because they have more kinds of bases in their DNA than the four used by prokaryotes. 
D)  That's not true; eukaryotes do not have more types of DNA polymerases. 
A)  the DNA-containing organelles have their own DNA polymerases. 
B)  they have linear DNA , which is harder to replicate than circular DNA. 
C)  because they have more kinds of bases in their DNA than the four used by prokaryotes. 
D)  That's not true; eukaryotes do not have more types of DNA polymerases.

Exam 10: Biosynthesis of Nucleic Acids: Replication

DNA repair mechanisms are essentially the same whether the DNA has minor damage or major damage.

In the original Central Dogma of biology,the ordinary flow of genetic information is:

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

Single strand binding proteins are important for this activity:

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

Why is thymine used in DNA rather than uracil?

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

Semiconservative replication implies that

One of the most important ways in which DNA is modified after synthesis is

DNA polymerase III from E.coli

The energetic driving force for nucleic acid synthesis is

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

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

A prokaryotic replisome typically contains two molecules of DNA pol III,but only one molecule of DNA pol I.Why?

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

Linear eukaryotic DNA molecules

How do origins of replication differ in eukaryotes and prokaryotes?

Which of the following is not an activity of DNA Polymerase I?

When the synthesis of new DNA is directed by an original template DNA molecule

Eukaryotes need more types of DNA polymerases than bacteria because

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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