Question 1

The repair of cyclobutane pyrimidine dimers involves bacterial ____ and the cofactors ____ and ____.

Accepted Answer

A)  DNA methylase; S-adenosyl methionine; ATP 
B)  DNA carboxylase; CoA; CoQ 
C)  DNA polymerase I; flavin; TPP 
D)  photolyase; flavin; NADH 
E)  photolyase; flavin; pterin 
A)  DNA methylase; S-adenosyl methionine; ATP 
B)  DNA carboxylase; CoA; CoQ 
C)  DNA polymerase I; flavin; TPP 
D)  photolyase; flavin; NADH 
E)  photolyase; flavin; pterin

Question 2

In the initiation of replication in yeast, the pre-replication complex (pre-RC) consists of all EXCEPT:

Accepted Answer

A)  MCM complex. 
B)  Cdc6p. 
C)  ORC. 
D)  CDKs. 
E)  all are true. 
A)  MCM complex. 
B)  Cdc6p. 
C)  ORC. 
D)  CDKs. 
E)  all are true.

Question 3

Mutations in DNA may result from all of the following EXCEPT:

Accepted Answer

A)  spontaneous mutations due to errors in replication. 
B)  physical insults on the cell, such as UV light. 
C)  errors in transcription. 
D)  chemical mutagens. 
E)  introduction of a base analog into DNA. 
A)  spontaneous mutations due to errors in replication. 
B)  physical insults on the cell, such as UV light. 
C)  errors in transcription. 
D)  chemical mutagens. 
E)  introduction of a base analog into DNA.

Question 4

When the methyl-directed repair system detects a mismatch in dsDNA it:

Accepted Answer

A)  corrects the DNA strand that is methylated by removal of a single base and replacing with the correct one 
B)  corrects the DNA strand that is methylated by removal of a sting of nucleotides and replacing with correctly matched nucleotides 
C)  corrects the DNA strand that is not methylated by removal of a single base and replacing with the correct one 
D)  corrects the DNA strand that is not methylated by removal of a sting of nucleotides and replacing with correctly matched nucleotides 
E)  none of the above. 
A)  corrects the DNA strand that is methylated by removal of a single base and replacing with the correct one 
B)  corrects the DNA strand that is methylated by removal of a sting of nucleotides and replacing with correctly matched nucleotides 
C)  corrects the DNA strand that is not methylated by removal of a single base and replacing with the correct one 
D)  corrects the DNA strand that is not methylated by removal of a sting of nucleotides and replacing with correctly matched nucleotides 
E)  none of the above.

Question 5

Together with ____, ____ provide(s) for genetic variability within species and, ultimately, the evolution of new species.

Accepted Answer

A)  DNA repair; DNA glycosylase 
B)  DNA glycosylase; recombination 
C)  recombination; mutations 
D)  mutations; DNA glycosylase 
E)  DNA repair; mutations 
A)  DNA repair; DNA glycosylase 
B)  DNA glycosylase; recombination 
C)  recombination; mutations 
D)  mutations; DNA glycosylase 
E)  DNA repair; mutations

Question 6

Which of the following statements explains why the thymine analog, 5-bromouracil (5-BU), can cause mutations in DNA when it is inserted in place of a site normally occupied by T?

Accepted Answer

A)  the bromine of 5-BU is similar in size to the methyl group of T and thus pairs with A 
B)  5-BU is often found as the enol tautomer that hydrogens more effectively with G than with A 
C)  the bromine is subject to nucleophilic attack by a methyl transferase resulting in newly synthesized DNA being recognized as the methylated parent strand 
D)  the 5-BU is subject to removal resulting in a frame-shift mutation 
E)  none of the above 
A)  the bromine of 5-BU is similar in size to the methyl group of T and thus pairs with A 
B)  5-BU is often found as the enol tautomer that hydrogens more effectively with G than with A 
C)  the bromine is subject to nucleophilic attack by a methyl transferase resulting in newly synthesized DNA being recognized as the methylated parent strand 
D)  the 5-BU is subject to removal resulting in a frame-shift mutation 
E)  none of the above

Question 7

Enzymes that catalyze the unwinding of DNA double helix are:

Accepted Answer

A)  topoisomerases. 
B)  helicases. 
C)  ligases. 
D)  gyrases. 
E)  polymerases. 
A)  topoisomerases. 
B)  helicases. 
C)  ligases. 
D)  gyrases. 
E)  polymerases.

Question 8

Which of the following would most likely cause a frameshift mutation?

Accepted Answer

A)  an alkylating agent such as methyl iodide 
B)  a base analog such as 5-bromouracil 
C)  a chemical mutagen such as nitrous acid 
D)  an intercalation agent such as acridine orange 
E)  none of the above 
A)  an alkylating agent such as methyl iodide 
B)  a base analog such as 5-bromouracil 
C)  a chemical mutagen such as nitrous acid 
D)  an intercalation agent such as acridine orange 
E)  none of the above

Question 9

The exchange of one base for another is called a ____, while insertions and deletions are referred to as ____.

Accepted Answer

A)  frameshift mutation; transition mutations 
B)  frameshift mutation; point mutations 
C)  point mutation; transversion mutations 
D)  point mutation; frameshift mutations 
E)  transition mutation; transversion mutations 
A)  frameshift mutation; transition mutations 
B)  frameshift mutation; point mutations 
C)  point mutation; transversion mutations 
D)  point mutation; frameshift mutations 
E)  transition mutation; transversion mutations

Question 10

A transversion mutation would be replacing T by:

Accepted Answer

A)  A. 
B)  C. 
C)  U. 
D)  G. 
E)  either A or G. 
A)  A. 
B)  C. 
C)  U. 
D)  G. 
E)  either A or G.

Question 11

In base-excision repair, the first enzyme in the sequence is ____ creating a(n) ____ site.

Accepted Answer

A)  DNA polymerase III; ligase binding 
B)  DNA glycosylase; apurinic or apyrimidinic 
C)  DNA polymerase I; apurinic or apyrimidinic 
D)  DNA ligase; polymerase III binding 
E)  AP endonuclease; ligase binding 
A)  DNA polymerase III; ligase binding 
B)  DNA glycosylase; apurinic or apyrimidinic 
C)  DNA polymerase I; apurinic or apyrimidinic 
D)  DNA ligase; polymerase III binding 
E)  AP endonuclease; ligase binding

Question 12

The termination of DNA replication in E. coli occurs when ____ protein binds the ____ locus on the DNA and acts as a ____.

Accepted Answer

A)  tag; oriC; helicase 
B)  ter; tag; polymerase 
C)  DnaC; DnaG; gyrase 
D)  Tus; Ter; contrahelicase 
E)  SSB; primer; RNA polymerase 
A)  tag; oriC; helicase 
B)  ter; tag; polymerase 
C)  DnaC; DnaG; gyrase 
D)  Tus; Ter; contrahelicase 
E)  SSB; primer; RNA polymerase

Question 13

E. coli DNA polymerase I has all of the following characteristics EXCEPT:

Accepted Answer

A)  a 5'→3' exonuclease activity. 
B)  a 3'→5' exonuclease activity. 
C)  a 5'→3' DNA polymerase activity. 
D)  modest processivity (approximately 20 nucleotides). 
E)  does not require a primer for initiation. 
A)  a 5'→3' exonuclease activity. 
B)  a 3'→5' exonuclease activity. 
C)  a 5'→3' DNA polymerase activity. 
D)  modest processivity (approximately 20 nucleotides). 
E)  does not require a primer for initiation.

Question 14

Define the types of recombination. What are the enzymes of general recombination in E.coli?​

Accepted Answer

​Genetic recombination is the natural re

Question 15

All are correct about DNA gyrase in E. coli EXCEPT:

Accepted Answer

A)  It is a topoisomerase that hydrolyzes ATP during its reaction mechanism. 
B)  Its mechanism involves the breaking of a single phosphoester bond in one strand of dsDNA. 
C)  It works to remove positive supercoiling introduced by the DnaB protein (helicase). 
D)  It works to introduce negative supercoiling in DNA to overcome the torsion stress imposed upon unwinding. 
E)  All are true. 
A)  It is a topoisomerase that hydrolyzes ATP during its reaction mechanism. 
B)  Its mechanism involves the breaking of a single phosphoester bond in one strand of dsDNA. 
C)  It works to remove positive supercoiling introduced by the DnaB protein (helicase). 
D)  It works to introduce negative supercoiling in DNA to overcome the torsion stress imposed upon unwinding. 
E)  All are true.

Question 16

AZT (3'-azido-2',3'-dideoxythymidine) is a drug that gets incorporated into growing viral DNA and blocks the activity of:

Accepted Answer

A)  DNA ligase. 
B)  DNA polymerase β (beta). 
C)  DNA polymerase α (alpha). 
D)  reverse transcriptase. 
E)  none of the above. 
A)  DNA ligase. 
B)  DNA polymerase β (beta). 
C)  DNA polymerase α (alpha). 
D)  reverse transcriptase. 
E)  none of the above.

Question 17

Discuss insertions and deletions in DNA.​

Accepted Answer

The addition or removal of one or more b

Question 18

A pair of β-subunits of DNA polymerase III form a ____ to tether the polymerase to the template thus increasing the ____ of the polymerase.

Accepted Answer

A)  ligase; unwinding 
B)  sliding clamp; processivity 
C)  primer binding; primase activity 
D)  loop of DNA; direction 
E)  none are true 
A)  ligase; unwinding 
B)  sliding clamp; processivity 
C)  primer binding; primase activity 
D)  loop of DNA; direction 
E)  none are true

Question 19

Which of the following DNA repair mechanisms is correctly defined?

Accepted Answer

A)  mismatch repair system: corrects errors created from chemical modification of DNA 
B)  photolyase: repairs cyclobutane dimers formed between adjacent cytosine residues 
C)  base excision repair: uses DNA glycosylase to remove a damaged base by cleaving the glycosidic bond 
D)  nucleotide excision repair: removes a single nucleotide by cutting the phosphodiester backbone 
E)  none of the above 
A)  mismatch repair system: corrects errors created from chemical modification of DNA 
B)  photolyase: repairs cyclobutane dimers formed between adjacent cytosine residues 
C)  base excision repair: uses DNA glycosylase to remove a damaged base by cleaving the glycosidic bond 
D)  nucleotide excision repair: removes a single nucleotide by cutting the phosphodiester backbone 
E)  none of the above

Question 20

____ provides a mechanism for generating a variety of protein isoforms of immunoglobulins from a limited number of genes.

Accepted Answer

A)  Genetic recombination 
B)  Replication licensing 
C)  DNA polymerase 
D)  DNA rearrangement 
E)  All are true 
A)  Genetic recombination 
B)  Replication licensing 
C)  DNA polymerase 
D)  DNA rearrangement 
E)  All are true

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

The repair of cyclobutane pyrimidine dimers involves bacterial ____ and the cofactors ____ and ____.

In the initiation of replication in yeast, the pre-replication complex (pre-RC) consists of all EXCEPT:

Mutations in DNA may result from all of the following EXCEPT:

When the methyl-directed repair system detects a mismatch in dsDNA it:

Together with ____, ____ provide(s) for genetic variability within species and, ultimately, the evolution of new species.

Which of the following statements explains why the thymine analog, 5-bromouracil (5-BU), can cause mutations in DNA when it is inserted in place of a site normally occupied by T?

Enzymes that catalyze the unwinding of DNA double helix are:

Which of the following would most likely cause a frameshift mutation?

The exchange of one base for another is called a ____, while insertions and deletions are referred to as ____.

A transversion mutation would be replacing T by:

In base-excision repair, the first enzyme in the sequence is ____ creating a(n) ____ site.

The termination of DNA replication in E. coli occurs when ____ protein binds the ____ locus on the DNA and acts as a ____.

E. coli DNA polymerase I has all of the following characteristics EXCEPT:

Define the types of recombination. What are the enzymes of general recombination in E.coli?​

All are correct about DNA gyrase in E. coli EXCEPT:

AZT (3'-azido-2',3'-dideoxythymidine) is a drug that gets incorporated into growing viral DNA and blocks the activity of:

Discuss insertions and deletions in DNA.​

A pair of β-subunits of DNA polymerase III form a ____ to tether the polymerase to the template thus increasing the ____ of the polymerase.

Which of the following DNA repair mechanisms is correctly defined?

____ provides a mechanism for generating a variety of protein isoforms of immunoglobulins from a limited number of genes.

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

The repair of cyclobutane pyrimidine dimers involves bacterial and the cofactors and .

Together with , provide(s) for genetic variability within species and, ultimately, the evolution of new species.

The exchange of one base for another is called a , while insertions and deletions are referred to as .

In base-excision repair, the first enzyme in the sequence is creating a(n) site.

The termination of DNA replication in E. coli occurs when protein binds the locus on the DNA and acts as a .

Define the types of recombination. What are the enzymes of general recombination in E.coli?

Discuss insertions and deletions in DNA.

A pair of β-subunits of DNA polymerase III form a to tether the polymerase to the template thus increasing the of the polymerase.