Question 1

All of the following are characteristic of replication of the E. coli circular chromosome EXCEPT:

Accepted Answer

A)  replication is bi-directional. 
B)  it initiates at a unique position called oriC. 
C)  torsional stress introduced in the duplex DNA is relieved by DNA gyrase. 
D)  the unwinding of the duplex DNA is driven by the translocation of the DNA polymerase. 
E)  replication forks move in opposite directions. 
A)  replication is bi-directional. 
B)  it initiates at a unique position called oriC. 
C)  torsional stress introduced in the duplex DNA is relieved by DNA gyrase. 
D)  the unwinding of the duplex DNA is driven by the translocation of the DNA polymerase. 
E)  replication forks move in opposite directions. D

Question 2

Discuss pyrimidine dimers in DNA. How are they repaired?​

Accepted Answer

​UV irradiation promotes the formation of covalent bonds between adjacent thymine residues in a DNA strand, creating a cyclobutyl ring. Because the C-C bonds in this ring are shorter than the normal 0.34-nm base stacking in B-DNA, the DNA is distorted at this spot and is no longer a proper template for either replication or transcription. Photolyase (also called photoreactivating enzyme), a flavin- and pterin-dependent enzyme, binds at the dimer and uses the energy of visible light to break the cyclobutyl ring, restoring the pyrimidines to their original form.

Question 3

The enzyme that seals nicks in dsDNA where a 3'-OH and 5'-phosphate are juxtapositioned is:

Accepted Answer

A)  DNA polymerase I. 
B)  DNA gyrase. 
C)  DNA polymerase III. 
D)  DNA ligase. 
E)  primerase. 
A)  DNA polymerase I. 
B)  DNA gyrase. 
C)  DNA polymerase III. 
D)  DNA ligase. 
E)  primerase. D

Question 4

B-cells, T-cells, and macrophages are cell types capable of ____ as a mechanism of producing ____ essential to the immune response.

Accepted Answer

A)  replication rearrangement; antibodies 
B)  complimentarity modification; antigens 
C)  DNA replication; genes 
D)  DNA rearrangement; antibodies 
E)  All are true 
A)  replication rearrangement; antibodies 
B)  complimentarity modification; antigens 
C)  DNA replication; genes 
D)  DNA rearrangement; antibodies 
E)  All are true

Question 5

Eukaryotic cells have replication regions called ____ that occur every ____ kbp and the units of replication are called ____.

Accepted Answer

A)  replicons; 2-5; replication forks 
B)  replication factories; 5-10; replicons 
C)  replicators; 3-300; replicons 
D)  replication forks; 5-50; replicators 
E)  none are true 
A)  replicons; 2-5; replication forks 
B)  replication factories; 5-10; replicons 
C)  replicators; 3-300; replicons 
D)  replication forks; 5-50; replicators 
E)  none are true

Question 6

3'-Exonuclease activity of DNA polymerase I of E. coli has all the characteristics EXCEPT:

Accepted Answer

A)  is an "editor" of polymerase activity. 
B)  is opposite to the polymerase activity. 
C)  removes nucleotides that do not base pair at the 3'-end of the growing chain. 
D)  is relatively fast compared to the polymerase activity. 
E)  all are true. 
A)  is an "editor" of polymerase activity. 
B)  is opposite to the polymerase activity. 
C)  removes nucleotides that do not base pair at the 3'-end of the growing chain. 
D)  is relatively fast compared to the polymerase activity. 
E)  all are true.

Question 7

An RNA-dependent DNA polymerase that carries the RNA template with it to synthesize repeats at the 3'-ends of chromosomes is called:

Accepted Answer

A)  DNA ligase. 
B)  telomerase. 
C)  DNA polymerase γ (gamma). 
D)  topoisomerase. 
E)  DNA polymerase β (beta). 
A)  DNA ligase. 
B)  telomerase. 
C)  DNA polymerase γ (gamma). 
D)  topoisomerase. 
E)  DNA polymerase β (beta).

Question 8

All occur during DNA replication in E. coli EXCEPT:

Accepted Answer

A)  helicase unwinds dsDNA at the replication fork. 
B)  DNA ligase catalyzes the formation of phosphoester bonds on the lagging strand. 
C)  DNA polymerase I hydrolyzes RNA from the 5' ends of Okazaki fragments. 
D)  primase (DnaG) binds to a GC rich region of dsDNA in oriC. 
E)  all are true. 
A)  helicase unwinds dsDNA at the replication fork. 
B)  DNA ligase catalyzes the formation of phosphoester bonds on the lagging strand. 
C)  DNA polymerase I hydrolyzes RNA from the 5' ends of Okazaki fragments. 
D)  primase (DnaG) binds to a GC rich region of dsDNA in oriC. 
E)  all are true.

Question 9

Which of the following activities is NOT associated with the DNA polymerase III holoenzyme?

Accepted Answer

A)  3'-exonuclease 
B)  5'-exonuclease 
C)  sliding clamp 
D)  removal of single stranded binding proteins 
E)  all are activities of the holoenzyme 
A)  3'-exonuclease 
B)  5'-exonuclease 
C)  sliding clamp 
D)  removal of single stranded binding proteins 
E)  all are activities of the holoenzyme

Question 10

All are properties of DNA polymerase III EXCEPT:

Accepted Answer

A)  It is responsible for incorporating most of the nucleotides in the lagging strand. 
B)  It synthesizes most of the leading strand prior to aiding in the synthesis of the lagging strand. 
C)  It contains a 3' to 5' exonuclease activity. 
D)  It is a large protein complex containing more than five subunits. 
E)  Much greater processivity than DNA polymerase I. 
A)  It is responsible for incorporating most of the nucleotides in the lagging strand. 
B)  It synthesizes most of the leading strand prior to aiding in the synthesis of the lagging strand. 
C)  It contains a 3' to 5' exonuclease activity. 
D)  It is a large protein complex containing more than five subunits. 
E)  Much greater processivity than DNA polymerase I.

Question 11

Misincorporation of all subsequent amino acids results from ____ mutations.

Accepted Answer

A)  chemical 
B)  base shift 
C)  frameshift 
D)  transition 
E)  all are true 
A)  chemical 
B)  base shift 
C)  frameshift 
D)  transition 
E)  all are true

Question 12

The principal DNA polymerase in eukaryotic leading strand DNA replication is:

Accepted Answer

A)  DNA polymerase α (alpha). 
B)  DNA polymerase β (beta). 
C)  DNA polymerase γ (gamma). 
D)  DNA polymerase δ (delta). 
E)  DNA polymerase ε (epsilon). 
A)  DNA polymerase α (alpha). 
B)  DNA polymerase β (beta). 
C)  DNA polymerase γ (gamma). 
D)  DNA polymerase δ (delta). 
E)  DNA polymerase ε (epsilon).

Question 13

____ promotes the formation of covalent bonds between ____ thymine residues in a DNA strand creating a ____ ring called a thymidine dimer.

Accepted Answer

A)  Visible light; adjacent; cyclohexyl 
B)  Visible light; nearby; cyclobutyl 
C)  UV light; adjacent; cyclobutyl 
D)  UV light; nearby; cyclohexyl 
E)  IR light; adjacent; cyclobutyl 
A)  Visible light; adjacent; cyclohexyl 
B)  Visible light; nearby; cyclobutyl 
C)  UV light; adjacent; cyclobutyl 
D)  UV light; nearby; cyclohexyl 
E)  IR light; adjacent; cyclobutyl

Question 14

Compared to their parents, progeny may have new combinations of traits because of:

Accepted Answer

A)  reverse transcriptase. 
B)  cyclin dependent protein kinase. 
C)  genetic recombination. 
D)  processivity. 
E)  all are true. 
A)  reverse transcriptase. 
B)  cyclin dependent protein kinase. 
C)  genetic recombination. 
D)  processivity. 
E)  all are true.

Question 15

DNA is replicated by a ____ mechanism.

Accepted Answer

A)  dispersive 
B)  conservative 
C)  semiconservative 
D)  liberal 
E)  none of the above 
A)  dispersive 
B)  conservative 
C)  semiconservative 
D)  liberal 
E)  none of the above

Question 16

All are characteristics of transposons EXCEPT:

Accepted Answer

A)  segments of DNA moved non-enzymatically in the genome. 
B)  unstable location within genome. 
C)  range in size from hundreds of bps to 8 kbp. 
D)  the smallest transposons are called insertion sequences. 
E)  a major force in evolution. 
A)  segments of DNA moved non-enzymatically in the genome. 
B)  unstable location within genome. 
C)  range in size from hundreds of bps to 8 kbp. 
D)  the smallest transposons are called insertion sequences. 
E)  a major force in evolution.

Question 17

The vast diversity of immunoglobulin sequences is explained by:

Accepted Answer

A)  DNA rearrangement 
B)  large sections of DNA devoted to immunoglobulin formation 
C)  susceptibility of the immunoglobulin genes to mutation 
D)  sensitivity of formed immunoglobulin proteins to environmental factors 
E)  all of the above 
A)  DNA rearrangement 
B)  large sections of DNA devoted to immunoglobulin formation 
C)  susceptibility of the immunoglobulin genes to mutation 
D)  sensitivity of formed immunoglobulin proteins to environmental factors 
E)  all of the above

Question 18

SSBs are:

Accepted Answer

A)  substrates for DNA ligases. 
B)  supercoil stabilizing bodies. 
C)  single-stranded bodies called Okazaki fragments. 
D)  single-stranded DNA binding proteins that prevent re-annealing. 
E)  nucleases that hydrolyze single-stranded RNA primers. 
A)  substrates for DNA ligases. 
B)  supercoil stabilizing bodies. 
C)  single-stranded bodies called Okazaki fragments. 
D)  single-stranded DNA binding proteins that prevent re-annealing. 
E)  nucleases that hydrolyze single-stranded RNA primers.

Question 19

When the thymine analog, 5-bromouracil, incorporates into DNA normally occupied by thymine, what type of mutation can occur?

Accepted Answer

A)  T-A to A-T, only. 
B)  T-A to C-G, only. 
C)  C-G to T-A, only. 
D)  both b and c are correct. 
E)  a, b, and c are correct. 
A)  T-A to A-T, only. 
B)  T-A to C-G, only. 
C)  C-G to T-A, only. 
D)  both b and c are correct. 
E)  a, b, and c are correct.

Question 20

All are characteristic of retroviruses EXCEPT:

Accepted Answer

A)  uses viral DNA as a template. 
B)  reverse transcriptase is required to produce dsDNA for insertion into host genome 
C)  the viral RNA genome is degraded prior to complete synthesis of dsDNA 
D)  reverse transcriptase is often error-prone causing viruses to mutate quickly 
E)  genome can lie dormant for years as a provirus in the host chromosome. 
A)  uses viral DNA as a template. 
B)  reverse transcriptase is required to produce dsDNA for insertion into host genome 
C)  the viral RNA genome is degraded prior to complete synthesis of dsDNA 
D)  reverse transcriptase is often error-prone causing viruses to mutate quickly 
E)  genome can lie dormant for years as a provirus in the host chromosome.

Exam 28: Dna Metabolism: Replication, Recombination, and Repair

All of the following are characteristic of replication of the E. coli circular chromosome EXCEPT:

Discuss pyrimidine dimers in DNA. How are they repaired?​

The enzyme that seals nicks in dsDNA where a 3'-OH and 5'-phosphate are juxtapositioned is:

B-cells, T-cells, and macrophages are cell types capable of ____ as a mechanism of producing ____ essential to the immune response.

Eukaryotic cells have replication regions called ____ that occur every ____ kbp and the units of replication are called ____.

3'-Exonuclease activity of DNA polymerase I of E. coli has all the characteristics EXCEPT:

An RNA-dependent DNA polymerase that carries the RNA template with it to synthesize repeats at the 3'-ends of chromosomes is called:

All occur during DNA replication in E. coli EXCEPT:

Which of the following activities is NOT associated with the DNA polymerase III holoenzyme?

All are properties of DNA polymerase III EXCEPT:

Misincorporation of all subsequent amino acids results from ____ mutations.

The principal DNA polymerase in eukaryotic leading strand DNA replication is:

____ promotes the formation of covalent bonds between ____ thymine residues in a DNA strand creating a ____ ring called a thymidine dimer.

Compared to their parents, progeny may have new combinations of traits because of:

DNA is replicated by a ____ mechanism.

All are characteristics of transposons EXCEPT:

The vast diversity of immunoglobulin sequences is explained by:

SSBs are:

When the thymine analog, 5-bromouracil, incorporates into DNA normally occupied by thymine, what type of mutation can occur?

All are characteristic of retroviruses EXCEPT:

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids and the Peptide Bond

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, Tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Membranes and Membrane Transport

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Recombinant Dna, Cloning, Chimeric Genes, and Synthetic Biology

Enzymeskinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Metabolism: an Overview

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Lipid Biosynthesis

Nitrogen Acquisition and Amino Acid Metabolism

Synthesis and Degradation of Nucleotides

Metabolic Integration and Organ Specialization

Transcription and the Regulation of Gene Expression

Protein Synthesis

Completing the Protein Life Cycle: Folding, Processing, and Degradation

The Reception and Transmission of Extracellular Information

Filters

Discuss pyrimidine dimers in DNA. How are they repaired?

B-cells, T-cells, and macrophages are cell types capable of as a mechanism of producing essential to the immune response.

Eukaryotic cells have replication regions called that occur every kbp and the units of replication are called .

promotes the formation of covalent bonds between thymine residues in a DNA strand creating a ring called a thymidine dimer.