Question 1

In hereditary nonpolyposis colon cancer,mutations in MutS and MutH proteins result in the accumulation of mutations caused by

Accepted Answer

A) mismatched base pairs. 
B) structurally damaged bases. 
C) double-stranded DNA breaks. 
D) thymine dimers. 
E) DNA recombination. 
A) mismatched base pairs. 
B) structurally damaged bases. 
C) double-stranded DNA breaks. 
D) thymine dimers. 
E) DNA recombination.

Question 2

Homologous recombination may result in gene conversion when used to fix double-stranded DNA breaks because

Accepted Answer

A) sister chromatids are always identical. 
B) homologous recombination is prone to errors,potentially causing permanent genetic mutations. 
C) strand invasion may introduce new genes onto the damaged chromosome. 
D) homologous chromosomes may carry different alleles of the same gene. 
E) the Holliday junction may migrate,resulting in loss of genetic material. 
A) sister chromatids are always identical. 
B) homologous recombination is prone to errors,potentially causing permanent genetic mutations. 
C) strand invasion may introduce new genes onto the damaged chromosome. 
D) homologous chromosomes may carry different alleles of the same gene. 
E) the Holliday junction may migrate,resulting in loss of genetic material.

Question 3

Which of the following proteins is observed exclusively in association with eukaryotic DNA replication?

Accepted Answer

A) DNA polymerase I 
B) DNA gyrase 
C) single-strand binding proteins 
D) DNA ligase 
E) telomerase 
A) DNA polymerase I 
B) DNA gyrase 
C) single-strand binding proteins 
D) DNA ligase 
E) telomerase

Question 4

Which of the following is involved in proofreading during DNA replication?

Accepted Answer

A) 5' to 3' exonuclease activity of DNA polymerase 
B) 3' to 5' exonuclease activity of DNA polymerase 
C) 5' to 3' endonuclease activity of DNA polymerase 
D) 3' to 5' endonuclease activity of DNA polymerase 
E) RNA polymerase 
A) 5' to 3' exonuclease activity of DNA polymerase 
B) 3' to 5' exonuclease activity of DNA polymerase 
C) 5' to 3' endonuclease activity of DNA polymerase 
D) 3' to 5' endonuclease activity of DNA polymerase 
E) RNA polymerase

Question 5

Deamination is a spontaneous DNA mutation that converts cytosine to

Accepted Answer

A) thymine. 
B) guanine. 
C) adenine. 
D) uracil. 
E) None of these are correct. 
A) thymine. 
B) guanine. 
C) adenine. 
D) uracil. 
E) None of these are correct.

Question 6

The ________ pathway uses a set of proteins that bind to ends of two broken DNA fragments and join them together.

Accepted Answer

nonhomolog

Question 7

DNA replication is

Accepted Answer

A) conservative. 
B) dispersive. 
C) semiconservative. 
D) irregular. 
E) None of these selections apply. 
A) conservative. 
B) dispersive. 
C) semiconservative. 
D) irregular. 
E) None of these selections apply.

Question 8

The inherited disorder xeroderma pigmentosum causes extreme sensitivity to the sun because of defects in the ________ pathway.

Accepted Answer

nucleotide

Question 9

Strand slippage results in ________,which can cause a number of human diseases such as fragile X syndrome.

Accepted Answer

A) tautomeric shift 
B) double-stranded DNA breaks 
C) pyrimidine dimer addition 
D) deletion of large sections of DNA 
E) the re-replication of highly repetitive DNA sequences 
A) tautomeric shift 
B) double-stranded DNA breaks 
C) pyrimidine dimer addition 
D) deletion of large sections of DNA 
E) the re-replication of highly repetitive DNA sequences

Question 10

Several human disorders are caused by DNA repair pathway deficiencies.Choose one and describe: (1)what the deficiency is and (2)how the defect affects people with the disease.

Accepted Answer

There are many correct answers,so the in

Question 11

Telomerases are important in the complete replication of linear chromosomes because there is no ________ at the ends of the lagging strands.

Accepted Answer

The answer of Telomerases are important in the complete replication...

Question 12

________ synthesis is a damage-tolerant mechanism that allows synthesis of a new DNA strand from a damaged template.

Accepted Answer

The answer of ________ synthesis is a damage-tolerant mechanism that...

Question 13

The protein(s)that facilitate the unfolding of chromatin fibers ahead of the replication fork is (are)

Accepted Answer

A) helicase. 
B) scaffold proteins. 
C) chromatin remodeling proteins. 
D) replisomal proteins. 
E) helicase and scaffold proteins. 
A) helicase. 
B) scaffold proteins. 
C) chromatin remodeling proteins. 
D) replisomal proteins. 
E) helicase and scaffold proteins.

Question 14

Using specific examples,distinguish between those mutations that are spontaneous and those that are the result of exposure to substances or radiation.How might some of the mutagenic substances be used in cellular biology and medicine?

Accepted Answer

Spontaneous mutations are those that are

Question 15

Linear chromosomes have multiple sites of DNA replication known as ________.

Accepted Answer

The answer of Linear chromosomes have multiple sites of DNA...

Question 16

A NASA probe returned samples of rocks from the surface of Mars.From these rocks,a prokaryotic organism was isolated and remained viable under conditions similar to those of Mars.The organisms are capable of dividing to replicate themselves.In order to determine whether the DNA replication of these organisms was semiconservative,an experiment using N15/N14 (similar to that of Meselson and Stahl)was performed.If the method of DNA replication were conservative,after one generation one would expect to see

Accepted Answer

A) all of the DNA in the heavy (N15)band. 
B) all of the DNA in the light (N14)band. 
C) all of the DNA at a point midway between the heavy and light bands. 
D) half of the DNA in the light band,the other half in the heavy band. 
E) None of these are correct. 
A) all of the DNA in the heavy (N15)band. 
B) all of the DNA in the light (N14)band. 
C) all of the DNA at a point midway between the heavy and light bands. 
D) half of the DNA in the light band,the other half in the heavy band. 
E) None of these are correct.

Question 17

Spontaneous hydrolysis reactions between DNA and surrounding water molecules commonly cause

Accepted Answer

A) pyrimidine dimer formation. 
B) depurination. 
C) tautomeric shift. 
D) double-stranded DNA breaks. 
E) deletion mutations. 
A) pyrimidine dimer formation. 
B) depurination. 
C) tautomeric shift. 
D) double-stranded DNA breaks. 
E) deletion mutations.

Question 18

Which of the following proteins is observed exclusively in association with prokaryotic DNA replication?

Accepted Answer

A) DNA polymerase I 
B) primase 
C) helicase 
D) single-strand binding proteins 
E) telomerase 
A) DNA polymerase I 
B) primase 
C) helicase 
D) single-strand binding proteins 
E) telomerase

Question 19

DNA damage can occur

Accepted Answer

A) due to exposure to certain chemicals or radiation. 
B) spontaneously. 
C) during DNA replication. 
D) during transcription. 
E) during DNA replication,spontaneously,or due to exposure to certain chemicals or radiation. 
A) due to exposure to certain chemicals or radiation. 
B) spontaneously. 
C) during DNA replication. 
D) during transcription. 
E) during DNA replication,spontaneously,or due to exposure to certain chemicals or radiation.

Question 20

Compare and contrast nonhomologous end joining (NHEJ)and homologous recombination as methods of repairing double-stranded breaks in DNA.Under what conditions or in what organisms is homologous recombination not a likely mechanism for repair of double-stranded breaks?

Accepted Answer

NHEJ involves the recognition of broken

Exam 17: DNA Replication, repair, and Recombination

In hereditary nonpolyposis colon cancer,mutations in MutS and MutH proteins result in the accumulation of mutations caused by

Homologous recombination may result in gene conversion when used to fix double-stranded DNA breaks because

Which of the following proteins is observed exclusively in association with eukaryotic DNA replication?

Which of the following is involved in proofreading during DNA replication?

Deamination is a spontaneous DNA mutation that converts cytosine to

The ________ pathway uses a set of proteins that bind to ends of two broken DNA fragments and join them together.

DNA replication is

The inherited disorder xeroderma pigmentosum causes extreme sensitivity to the sun because of defects in the ________ pathway.

Strand slippage results in ________,which can cause a number of human diseases such as fragile X syndrome.

Several human disorders are caused by DNA repair pathway deficiencies.Choose one and describe: (1)what the deficiency is and (2)how the defect affects people with the disease.

Telomerases are important in the complete replication of linear chromosomes because there is no ________ at the ends of the lagging strands.

________ synthesis is a damage-tolerant mechanism that allows synthesis of a new DNA strand from a damaged template.

The protein(s)that facilitate the unfolding of chromatin fibers ahead of the replication fork is (are)

Using specific examples,distinguish between those mutations that are spontaneous and those that are the result of exposure to substances or radiation.How might some of the mutagenic substances be used in cellular biology and medicine?

Linear chromosomes have multiple sites of DNA replication known as ________.

Spontaneous hydrolysis reactions between DNA and surrounding water molecules commonly cause

Which of the following proteins is observed exclusively in association with prokaryotic DNA replication?

DNA damage can occur

Compare and contrast nonhomologous end joining (NHEJ)and homologous recombination as methods of repairing double-stranded breaks in DNA.Under what conditions or in what organisms is homologous recombination not a likely mechanism for repair of double-stranded breaks?

A Preview of Cell Biology

The Chemistry of the Cell

The Macromolecules of the Cell

Cells and Organelles

Bioenergetics: the Flow of Energy in the Cell

Enzymes: the Catalysts of Life

Membranes: Their Structure,function,and Chemistry

Transport Across Membranes: Overcoming the Permeability Barrier

Chemotrophic Energy Metabolism: Glycolysis and Fermentation

Chemotrophic Energy Metabolism: Aerobic Respiration

Phototrophic Energy Metabolism: Photosynthesis

The Endomembrane System

Cytoskeletal Systems

Cellular Movement: Motility and Contractility

Beyond the Cell: Cell Adhesions, cell Junctions, and Extracellular Structures

The Structural Basis of Cellular Information: Dna, chromosomes, and the Nucleus

Gene Expression: Ithe Genetic Code and Transcription

Gene Expression: Iiprotein Synthesis and Sorting

The Regulation of Gene Expression

Molecular Biology Techniques for Cell Biology

Signal Transduction Mechanisms: Ielectrical and Synaptic Signaling in Neurons

Signal Transduction Mechanisms: Iimessengers and Receptors

The Cell Cycle and Mitosis

Sexual Reproduction,meiosis,and Genetic Recombination

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