Question 1

A frameshift or phase shift mutation

Accepted Answer

A)  can only affect one polypeptide chain made from a polycistronic mRNA. 
B)  can usually be corrected by a missense mutation. 
C)  has little effect on most proteins. 
D)  could not occur in a regulatory gene. 
E)  None of the other answers is correct. 
A)  can only affect one polypeptide chain made from a polycistronic mRNA. 
B)  can usually be corrected by a missense mutation. 
C)  has little effect on most proteins. 
D)  could not occur in a regulatory gene. 
E)  None of the other answers is correct. E

Question 2

Helicase

Accepted Answer

A)  unwinds double stranded DNA by breaking base pairs. 
B)  will decrease the writhing number of negatively supercoiled DNA. 
C)  will increase the linking number of negatively supercoiled DNA. 
D)  nicks one strand of double stranded DNA. 
E)  cuts both strands of double stranded DNA. 
A)  unwinds double stranded DNA by breaking base pairs. 
B)  will decrease the writhing number of negatively supercoiled DNA. 
C)  will increase the linking number of negatively supercoiled DNA. 
D)  nicks one strand of double stranded DNA. 
E)  cuts both strands of double stranded DNA. A

Question 3

Semiconservative replication of DNA means that after two rounds of replication

Accepted Answer

A)  only one of the two parental strands is preserved intact in the progeny molecules of DNA. 
B)  both parental strands remain intact in one of the progeny molecules of DNA. 
C)  the two parental strands remain intact in different progeny molecules. 
D)  one of the parental strands is broken down and dispersed in one of the progeny molecules of DNA, the other parental strand remains intact in one of the progeny molecules. 
E)  neither of the parental strands appears in the progeny molecules of DNA. 
A)  only one of the two parental strands is preserved intact in the progeny molecules of DNA. 
B)  both parental strands remain intact in one of the progeny molecules of DNA. 
C)  the two parental strands remain intact in different progeny molecules. 
D)  one of the parental strands is broken down and dispersed in one of the progeny molecules of DNA, the other parental strand remains intact in one of the progeny molecules. 
E)  neither of the parental strands appears in the progeny molecules of DNA. C

Question 4

Which of the following are not required by DNA ligase in order to carry out its enzymatic reaction?

Accepted Answer

A)  a free OH 
B)  a free 5'-OH 
C)  a nick in DNA 
D)  either NAD or ATP 
E)  a template strand opposite the nick 
A)  a free OH 
B)  a free 5'-OH 
C)  a nick in DNA 
D)  either NAD or ATP 
E)  a template strand opposite the nick

Question 5

When we say DNA polymerase III has high processivity, we mean

Accepted Answer

A)  that it has 5' to nuclease activity. 
B)  that it has to 5' nuclease activity. 
C)  it makes few errors during DNA synthesis. 
D)  it stays bound to the DNA until the synthesis is finished. 
E)  it rapidly associates and dissociates with the DNA. 
A)  that it has 5' to nuclease activity. 
B)  that it has to 5' nuclease activity. 
C)  it makes few errors during DNA synthesis. 
D)  it stays bound to the DNA until the synthesis is finished. 
E)  it rapidly associates and dissociates with the DNA.

Question 6

With respect to mutations

Accepted Answer

A)  transitions arise from the replacement of one purine to another purine or one pyrimidine to another pyrimidine. 
B)  transversions arise from the replacement of one pyrimidine to another pyrimidine. 
C)  transitions arise through deletions of a nucleotide in the DNA sequence. 
D)  transversions arise through the insertion of a nucleotide in the DNA sequence. 
E)  both transitions and transversions cause frameshift mutations. 
A)  transitions arise from the replacement of one purine to another purine or one pyrimidine to another pyrimidine. 
B)  transversions arise from the replacement of one pyrimidine to another pyrimidine. 
C)  transitions arise through deletions of a nucleotide in the DNA sequence. 
D)  transversions arise through the insertion of a nucleotide in the DNA sequence. 
E)  both transitions and transversions cause frameshift mutations.

Question 7

Chemical damage to nuclear DNA from exposure to a mutagenic agent is most dangerous when

Accepted Answer

A)  the resulting mutation is repaired prior to replication of the damaged DNA. 
B)  the resulting mutation causes a permanent substitution of a single amino acid in an important protein with a chemically similar amino acid 
C)  the mutagenic agent causes a frameshift mutation near the amino terminus of a protein which promotes spermatogenesis. 
D)  the chemical change in the DNA results in a silent mutation which is fixed via DNA replication. 
E)  the resulting mutation is fixed through DNA replication and leads to the activation of a cellular oncogene and malignant transformation in a liver cell. 
A)  the resulting mutation is repaired prior to replication of the damaged DNA. 
B)  the resulting mutation causes a permanent substitution of a single amino acid in an important protein with a chemically similar amino acid 
C)  the mutagenic agent causes a frameshift mutation near the amino terminus of a protein which promotes spermatogenesis. 
D)  the chemical change in the DNA results in a silent mutation which is fixed via DNA replication. 
E)  the resulting mutation is fixed through DNA replication and leads to the activation of a cellular oncogene and malignant transformation in a liver cell.

Question 8

5'-Methylcytosine residues in DNA are "hot spots" for mutation because they

Accepted Answer

A)  can be deaminated to thymine. 
B)  can stimulate Z-DNA formation. 
C)  can easily tautomerize. 
D)  cannot base pair with guanine. 
A)  can be deaminated to thymine. 
B)  can stimulate Z-DNA formation. 
C)  can easily tautomerize. 
D)  cannot base pair with guanine.

Question 9

Which of the following DNA replication enzymes has a major role in lagging strand synthesis, but only a minor role in leading strand synthesis?

Accepted Answer

A)  DNA gyrase 
B)  DNA polymerase I 
C)  DNA polymerase delta 
D)  DNA polymerase III 
A)  DNA gyrase 
B)  DNA polymerase I 
C)  DNA polymerase delta 
D)  DNA polymerase III

Question 10

Okazaki fragments are

Accepted Answer

A)  the RNA primer in DNA synthesis. 
B)  pieces of DNA produced by restriction enzyme digestion. 
C)  unique to eukaryotes. 
D)  RNA fragments produced by splicing of primary transcripts. 
E)  stretches of DNA synthesized on the lagging strand. 
A)  the RNA primer in DNA synthesis. 
B)  pieces of DNA produced by restriction enzyme digestion. 
C)  unique to eukaryotes. 
D)  RNA fragments produced by splicing of primary transcripts. 
E)  stretches of DNA synthesized on the lagging strand.

Question 11

The protein involved in separating the DNA strands at the initiation of DNA replication is called

Accepted Answer

A)  helicase. 
B)  DNA polymerase I. 
C)  DNA polymerase III. 
D)  primase. 
E)  DNA gyrase. 
A)  helicase. 
B)  DNA polymerase I. 
C)  DNA polymerase III. 
D)  primase. 
E)  DNA gyrase.

Question 12

Which of the following is specific to prokaryotes?

Accepted Answer

A)  DNA replication is tied to the cell cycle. 
B)  The replication template is chromatin. 
C)  Each chromosome has multiple origins of replication. 
D)  Chromosomal DNA is linear. 
E)  DNA replication uses DNA polymerase III. 
A)  DNA replication is tied to the cell cycle. 
B)  The replication template is chromatin. 
C)  Each chromosome has multiple origins of replication. 
D)  Chromosomal DNA is linear. 
E)  DNA replication uses DNA polymerase III.

Question 13

Replication of the DNA in a human chromosome is similar to E. coli DNA replication in all of the following EXCEPT

Accepted Answer

A)  replication is semiconservative. 
B)  the lagging strand is synthesized discontinuously. 
C)  multiple DNA polymerases are involved. 
D)  RNA is used as a primer. 
E)  only one origin is involved per DNA molecule. 
A)  replication is semiconservative. 
B)  the lagging strand is synthesized discontinuously. 
C)  multiple DNA polymerases are involved. 
D)  RNA is used as a primer. 
E)  only one origin is involved per DNA molecule.

Question 14

The formation of tautomers of the DNA bases can be mutagenic because they can cause

Accepted Answer

A)  depurination. 
B)  strand breakage. 
C)  abnormal base pairing. 
D)  cross-linking. 
A)  depurination. 
B)  strand breakage. 
C)  abnormal base pairing. 
D)  cross-linking.

Question 15

Which of the following are not required by DNA ligase in order to carry out its enzymatic reaction?

Accepted Answer

A)  a free 3'-OH 
B)  a free 5'-OH 
C)  a nick in DNA 
D)  either NAD or ATP 
E)  a template strand opposite the nick 
A)  a free 3'-OH 
B)  a free 5'-OH 
C)  a nick in DNA 
D)  either NAD or ATP 
E)  a template strand opposite the nick

Question 16

Which of the following enzymes is the most sensitive to inhibition by alpha-amanitin?

Accepted Answer

A)  prokaryotic DNA polymerase I 
B)  prokaryotic DNA polymerase III 
C)  eukaryotic DNA polymerase alpha 
D)  eukaryotic RNA polymerase I 
E)  eukaryotic RNA polymerase II 
A)  prokaryotic DNA polymerase I 
B)  prokaryotic DNA polymerase III 
C)  eukaryotic DNA polymerase alpha 
D)  eukaryotic RNA polymerase I 
E)  eukaryotic RNA polymerase II

Question 17

A template in molecular biology means

Accepted Answer

A)  the sequence of DNA to which the DNA polymerase initially binds. 
B)  a protein that has a specific binding site for RNA. 
C)  any macromolecule that provides the pattern for synthesis of another. 
D)  a polymer that provides the starting point for further growth of the molecule. 
E)  a temperature sensitive mutant. 
A)  the sequence of DNA to which the DNA polymerase initially binds. 
B)  a protein that has a specific binding site for RNA. 
C)  any macromolecule that provides the pattern for synthesis of another. 
D)  a polymer that provides the starting point for further growth of the molecule. 
E)  a temperature sensitive mutant.

Question 18

Which is the complementary strand of this sequence: 3' AGTCAGACCAGAC 5'?

Accepted Answer

A)  5' AGTCAGACCAGAC 3' 
B)  3' GTCTGGTCTGACT 5' 
C)  5' GTCTGGTCTGACT 3' 
D)  5' CAGACCAGACTGA 3' 
A)  5' AGTCAGACCAGAC 3' 
B)  3' GTCTGGTCTGACT 5' 
C)  5' GTCTGGTCTGACT 3' 
D)  5' CAGACCAGACTGA 3'

Question 19

DNA replication involves all the factors listed EXCEPT

Accepted Answer

A)  DNA polymerase. 
B)  sigma factor. 
C)  single stranded DNA template and primer. 
D)  RNA polymerase. 
E)  deoxyribonucleoside triphosphates. 
A)  DNA polymerase. 
B)  sigma factor. 
C)  single stranded DNA template and primer. 
D)  RNA polymerase. 
E)  deoxyribonucleoside triphosphates.

Question 20

In eukaryotes, which DNA polymerase is responsible for the replication of mitochondrial DNA?

Accepted Answer

A)  alpha 
B)  beta 
C)  gamma 
D)  delta 
E)  epsilon 
A)  alpha 
B)  beta 
C)  gamma 
D)  delta 
E)  epsilon

Exam 4: DNA Replication, Recombination, and Repair

A frameshift or phase shift mutation

Helicase

Semiconservative replication of DNA means that after two rounds of replication

Which of the following are not required by DNA ligase in order to carry out its enzymatic reaction?

When we say DNA polymerase III has high processivity, we mean

With respect to mutations

Chemical damage to nuclear DNA from exposure to a mutagenic agent is most dangerous when

5'-Methylcytosine residues in DNA are "hot spots" for mutation because they

Which of the following DNA replication enzymes has a major role in lagging strand synthesis, but only a minor role in leading strand synthesis?

Okazaki fragments are

The protein involved in separating the DNA strands at the initiation of DNA replication is called

Which of the following is specific to prokaryotes?

Replication of the DNA in a human chromosome is similar to E. coli DNA replication in all of the following EXCEPT

The formation of tautomers of the DNA bases can be mutagenic because they can cause

Which of the following are not required by DNA ligase in order to carry out its enzymatic reaction?

Which of the following enzymes is the most sensitive to inhibition by alpha-amanitin?

A template in molecular biology means

Which is the complementary strand of this sequence: 3' AGTCAGACCAGAC 5'?

DNA replication involves all the factors listed EXCEPT

In eukaryotes, which DNA polymerase is responsible for the replication of mitochondrial DNA?

Eukaryotic Cell Structure

DNA and RNA: Composition and Structure

Protein I: Composition and Structure

RNA: Transcription and Rna Processing

Protein Synthesis: Translation and Posttranslational Modifications

Recombinant Dna and Biotechnology

Regulation of Gene Expression

Protein II: Structure-Function Relationships in Protein Families

Enzymes: Classification, Kinetics, and Control

The Cytochromes P450 and Nitric Oxide Synthases

Biological Membranes: Structure and Membrane Transport

Fundamentals of Signal Transduction

Bioenergetics and Oxidative Metabolism

Carbohydrate Metabolism I: Major Metabolic Pathways and Their Control

Carbohydrate Metabolism II: Special Pathways and Glycoconjugates

Lipid Metabolism I: Synthesis, Storage, and Utilization of Fatty Acids and Triacylglycerols

Lipid Metabolism II: Pathways of Metabolism of Special Lipids

Amino Acid Metabolism

Purine and Pyrimidine Nucleotide Metabolism

Metabolic Interrelationships

Biochemistry of Hormones

Molecular Cell Biology

Cell Cycle, Programmed Cell Death, and Cancer

Digestion and Absorption of Basic Nutritional Constituents

Digestion and Absorption of Basic Nutritional Constituents

Principles of Nutrition I and II

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