Question 1

Semiconservative replication of DNA was established experimentally by

Accepted Answer

A)  gel electrophoresis. 
B)  ultraviolet spectroscopy. 
C)  column chromatography. 
D)  density-gradient centrifugation. 
A)  gel electrophoresis. 
B)  ultraviolet spectroscopy. 
C)  column chromatography. 
D)  density-gradient centrifugation.

Question 2

The mechanism of breakage and reunion of DNA strands during recombination was proposed by:

Accepted Answer

A)  Messelson and Stahl 
B)  Messelson and Weigle 
C)  Robin Holliday 
D)  Francis Crick 
A)  Messelson and Stahl 
B)  Messelson and Weigle 
C)  Robin Holliday 
D)  Francis Crick

Question 3

A prokaryotic replisome typically contains three 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 4

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 5

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 6

The DNA polymerases in eukaryotes have similar functions to those found in bacteria, but they are not identical.

Accepted Answer

A) True 
 B)False

Question 7

Which of the following is not required for optimal DNA replication?

Accepted Answer

A)  Primase 
B)  DNA Polymerase II. 
C)  Single strand binding proteins. 
D)  Gyrase 
E)  All of these are necessary. 
A)  Primase 
B)  DNA Polymerase II. 
C)  Single strand binding proteins. 
D)  Gyrase 
E)  All of these are necessary.

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

Which of the following is NOT an observed event in the flow of genetic information?

Accepted Answer

A)  DNA --> RNA 
B)  RNA --> DNA 
C)  RNA --> RNA 
D)  DNA --> DNA 
E)  RNA --> Protein
F) Protein --> RNA
G) All of the choices ARE observed 
A)  DNA --> RNA 
B)  RNA --> DNA 
C)  RNA --> RNA 
D)  DNA --> DNA 
E)  RNA --> Protein
F) Protein --> RNA
G) All of the choices ARE observed

Question 10

If replication were conservative instead of semi-conservative, the famous Meselson and Stahl experiment would have shown which of the following results after the first round of replication?

Accepted Answer

A)  All of the double helices would have been heavy chains 
B)  All of the double helices would have been light chains 
C)  Half of the double helices would have been all heavy chains and the other half would have been all light chains 
D)  All of the double helices would have been a combination of a heavy strand and a light strand 
A)  All of the double helices would have been heavy chains 
B)  All of the double helices would have been light chains 
C)  Half of the double helices would have been all heavy chains and the other half would have been all light chains 
D)  All of the double helices would have been a combination of a heavy strand and a light strand

Question 11

Recombination:

Accepted Answer

A)  occurs randomly throughout a chromosome 
B)  occurs more often in areas called hot spots 
C)  is a process that only happens under controlled laboratory conditions 
D)  is a spontaneous process that requires no enzymes 
A)  occurs randomly throughout a chromosome 
B)  occurs more often in areas called hot spots 
C)  is a process that only happens under controlled laboratory conditions 
D)  is a spontaneous process that requires no enzymes

Question 12

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 13

The primer for in vivo DNA replication is:

Accepted Answer

A)  The 3' hydroxyl of the preceding Okazaki fragment. 
B)  A short piece of RNA. 
C)  A nick made in the DNA template. 
D)  A primer is not always required for DNA replication. 
E)  All of these are true. 
A)  The 3' hydroxyl of the preceding Okazaki fragment. 
B)  A short piece of RNA. 
C)  A nick made in the DNA template. 
D)  A primer is not always required for DNA replication. 
E)  All of these are true.

Question 14

All the following describe the general mechanism of DNA synthesis, except :

Accepted Answer

A)  From the perspective of the DNA template strands, one strand is made 5' → 3' while the other strand is made 3' → 5'. 
B)  The strands become separated during synthesis. 
C)  Synthesis occurs in both directions from the starting site of synthesis. 
D)  Synthesis of DNA is a very accurate process. 
E)  All of these are correct. 
A)  From the perspective of the DNA template strands, one strand is made 5' → 3' while the other strand is made 3' → 5'. 
B)  The strands become separated during synthesis. 
C)  Synthesis occurs in both directions from the starting site of synthesis. 
D)  Synthesis of DNA is a very accurate process. 
E)  All of these are correct.

Question 15

In order to replicate both strands, E. coli

Accepted Answer

A)  displaces one of the strands and folds it back so both strands face in the same direction, so they can be synthesized at once. 
B)  synthesizes each strand in the opposite direction (one 5' → 3', one 3' → 5'), so they can be synthesized at once. 
C)  only synthesizes one strand at a time. 
A)  displaces one of the strands and folds it back so both strands face in the same direction, so they can be synthesized at once. 
B)  synthesizes each strand in the opposite direction (one 5' → 3', one 3' → 5'), so they can be synthesized at once. 
C)  only synthesizes one strand at a time.

Question 16

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 17

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 18

Which of the following activities does E. coli DNA polymerase III lack ?

Accepted Answer

A)  5' → 3' polymerase 
B)  5' → 3' exonuclease 
C)  3' → 5' exonuclease 
D)  E. coli DNA polymerase III has ALL of the above activities. 
A)  5' → 3' polymerase 
B)  5' → 3' exonuclease 
C)  3' → 5' exonuclease 
D)  E. coli DNA polymerase III has ALL of the above activities.

Question 19

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 20

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.

Exam 10: Biosynthesis of Nucleic Acids Replication

Semiconservative replication of DNA was established experimentally by

The mechanism of breakage and reunion of DNA strands during recombination was proposed by:

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

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

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

The DNA polymerases in eukaryotes have similar functions to those found in bacteria, but they are not identical.

Which of the following is not required for optimal DNA replication?

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

Which of the following is NOT an observed event in the flow of genetic information?

If replication were conservative instead of semi-conservative, the famous Meselson and Stahl experiment would have shown which of the following results after the first round of replication?

Recombination:

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

The primer for in vivo DNA replication is:

All the following describe the general mechanism of DNA synthesis, except :

In order to replicate both strands, E. coli

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

Semiconservative replication implies that

Which of the following activities does E. coli DNA polymerase III lack ?

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

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

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