Question 1

Hereditary nonpolyposis colorectal cancer (HNPCC) is an inherited disorder.The genetic defect identified is an error in the mismatch repair mechanism.Which of the following would be an expected result of this mutation?

Accepted Answer

A)  increased rate of errors by wild-type DNA polymerase
B)  increased rate of formation of pyrimidine dimers
C)  increased rate of repair of pyrimidine dimers
D)  decreased ability to repair certain DNA mutationsE) B) and D)
F) None of the above

Question 2

Figure 14.1
-Refer to Figure 14.1.What bases will be added to the primer as DNA replication proceeds? The bases should appear in the order that they will be added starting at the 5' end of the new strand.

Accepted Answer

A)  C,A,G,C,A,G,A
B)  T,C,T,G,C,T,G
C)  A,G,A,C,G,A,C
D)  G,T,C,G,T,C,TE) All of the above
F) None of the above

Question 3

Figure 14.2
-In Figure 14.2,which is the template strand?

Accepted Answer

A)  a
B)  b
C)  c
D)  dE) All of the above
F) C) and D)

Question 4

Which of the following are important in reducing the errors in DNA replication in E.coli organisms?

Accepted Answer

A)  proofreading activity of the epsilon subunit of DNA polymerase III
B)  mismatch repair
C)  nucleotide excision repair
D)  All of the above minimize errors in DNA replication in E.coli.E) A) and D)
F) C) and D) D

Question 5

Figure 14.2
-Identify the lagging strand during duplication of DNA starting from a double helix in Figure 14.2.

Accepted Answer

A)  a
B)  b
C)  c
D)  dE) C) and D)
F) A) and B)

Question 6

Watson and Crick elucidated the structure of DNA in 1953.Their research built on and helped explain the findings of other scientists before them,including _____.

Accepted Answer

A)  X-ray diffraction studies by Rosalind Franklin and Maurice Wilkins.
B)  Replication studies by Meselson and Stahl.
C)  Okazaki's work on lagging-strand DNA fragments.
D)  All of the above were important considerations in the elucidation of the structure of DNA.E) C) and D)
F) A) and B) A

Question 7

Telomere shortening is a problem in which types of cells?

Accepted Answer

A)  prokaryotes
B)  eukaryotes
C)  both prokaryotes and eukaryotesD) All of the above
E) None of the above

Question 8

DNA replication is highly accurate.It results in about one mistake per billion nucleotides.For the human genome,how often would errors occur?

Accepted Answer

A)  on average,once or twice in the lifetime of an individual
B)  on average,6 times each time the entire genome of a cell is replicated
C)  on average,once every 6 cell divisions
D)  on average,once a lifetime in 10% of the populationE) A) and D)
F) All of the above

Question 9

Who performed the classic experiments that proved DNA was copied by semiconservative replication?

Accepted Answer

A)  Watson and Crick
B)  Meselson and Stahl
C)  Hershey and Chase
D)  Franklin and WilkinsE) None of the above
F) B) and C) B

Question 10

In the mismatch repair process,enzyme complexes replace bases that were incorrectly inserted into the newly synthesized DNA strand.To function,they must be able to distinguish between the parent DNA strand and the new strand.How is this accomplished?

Accepted Answer

A)  The new strand contains the diphosphate bases.
B)  The parent strand is methylated.
C)  The new strand contains ribose sugars.
D)  The parent strand is usually radiolabeled.E) B) and C)
F) B) and D)

Question 11

The epsilon (ε) subunit of DNA polymerase III of E.coli has exonuclease activity.How does it function in the proofreading process?

Accepted Answer

A)  The epsilon subunit can remove a mismatched nucleotide.
B)  The epsilon subunit excises a segment of DNA around the mismatched base.
C)  The epsilon subunit can recognize which strand is the template or parent strand,and which is the new strand of DNA.
D)  It adds nucleotide triphosphates to the 3′ end of the growing DNA strand.E) A) and B)
F) All of the above

Question 12

Semiconservative replication involves a template.What is the template?

Accepted Answer

A)  single-stranded binding proteins
B)  DNA polymerase contains the template needed.
C)  one strand of the DNA molecule
D)  an RNA moleculeE) A) and B)
F) All of the above

Question 13

Which of the following would be least likely to cause DNA damage in an individual suffering from xeroderma pigmentosum?

Accepted Answer

A)  natural lighting
B)  low-level ultraviolet lights
C)  incandescent lightbulbs
D)  reflected sunlightE) All of the above
F) A) and B)

Question 14

What is a major difference between eukaryotic DNA replication and prokaryotic DNA replication?

Accepted Answer

A)  Prokaryotic replication does not require a primer.
B)  Prokaryotic chromosomes have a single origin of replication,while eukaryotic chromosomes have multiple origins of replication.
C)  DNA polymerase III of eukaryotes has both endonuclease and exonuclease activity,while that of prokaryotes has only exonuclease activity.
D)  DNA polymerases of prokaryotes can add nucleotides to both 3′ and 5′ ends of DNA strands,while those of eukaryotes function only in the 5′→3′ direction.E) B) and C)
F) None of the above

Question 15

Which of the following cells do not have active telomerase activity?

Accepted Answer

A)  most normal somatic cells
B)  most normal germ cells
C)  most cancer cellsD) All of the above
E) B) and C)

Question 16

What is the difference between the leading strand and the lagging strand in DNA replication?

Accepted Answer

A)  The leading strand is synthesized in the 3′→5′ direction in a discontinuous fashion,while the lagging strand is synthesized in the 5′→3′ direction in a continuous fashion.
B)  The leading strand requires an RNA primer,whereas the lagging strand does not.
C)  The leading strand is synthesized continuously in the 5′→3′ direction,while the lagging strand is synthesized discontinuously in the 5′→3′ direction.
D)  There are different DNA polymerases involved in elongation of the leading strand and the lagging strand.E) B) and C)
F) A) and C)

Question 17

Figure 14.3
-Refer to Figure 14.3.Which of the structures in the figure breaks hydrogen bonds between complementary bases?

Accepted Answer

The answer of  
Figure 14.3
-Refer to Figure 14.3.Which of...

Question 18

DNA is synthesized through a process known as _____.

Accepted Answer

A)  semiconservative replication
B)  conservative replication
C)  translation
D)  transcriptionE) None of the above
F) All of the above

Question 19

In a healthy cell,the rate of DNA repair is equal to the rate of DNA mutation.When the rate of repair lags behind the rate of mutation,what is a possible fate of the cell?

Accepted Answer

A)  The cell can be transformed to a cancerous cell.
B)  RNA may be used instead of DNA as inheritance material.
C)  It will become embryonic.
D)  DNA synthesis will continue in an attempt to repair itself.E) B) and D)
F) All of the above

Question 20

DNA contains the template needed to copy itself,but as you learned in Chapter 4,it has no catalytic activity.What catalyzes the formation of phosphodiester bonds between adjacent nucleotides in the DNA polymer being formed?

Accepted Answer

A)  ribozymes
B)  DNA polymerase
C)  ATP
D)  deoxyribonucleotide triphosphatesE) A) and B)
F) A) and D)

Exam 14: Dna and the Gene: Synthesis and Repair

Hereditary nonpolyposis colorectal cancer (HNPCC) is an inherited disorder.The genetic defect identified is an error in the mismatch repair mechanism.Which of the following would be an expected result of this mutation?

Correct AnswerverifiedShow Answer

Figure 14.1 -Refer to Figure 14.1.What bases will be added to the primer as DNA replication proceeds? The bases should appear in the order that they will be added starting at the 5' end of the new strand.

Correct AnswerverifiedShow Answer

Figure 14.2 -In Figure 14.2,which is the template strand?

Correct AnswerverifiedShow Answer

Which of the following are important in reducing the errors in DNA replication in E.coli organisms?

Correct AnswerverifiedD

Figure 14.2 -Identify the lagging strand during duplication of DNA starting from a double helix in Figure 14.2.

Correct AnswerverifiedShow Answer

Watson and Crick elucidated the structure of DNA in 1953.Their research built on and helped explain the findings of other scientists before them,including _____.

Correct AnswerverifiedA

Telomere shortening is a problem in which types of cells?

Correct AnswerverifiedShow Answer

DNA replication is highly accurate.It results in about one mistake per billion nucleotides.For the human genome,how often would errors occur?

Correct AnswerverifiedShow Answer

Who performed the classic experiments that proved DNA was copied by semiconservative replication?

Correct AnswerverifiedB

In the mismatch repair process,enzyme complexes replace bases that were incorrectly inserted into the newly synthesized DNA strand.To function,they must be able to distinguish between the parent DNA strand and the new strand.How is this accomplished?

Correct AnswerverifiedShow Answer

The epsilon (ε) subunit of DNA polymerase III of E.coli has exonuclease activity.How does it function in the proofreading process?

Correct AnswerverifiedShow Answer

Semiconservative replication involves a template.What is the template?

Correct AnswerverifiedShow Answer

Which of the following would be least likely to cause DNA damage in an individual suffering from xeroderma pigmentosum?

Correct AnswerverifiedShow Answer

What is a major difference between eukaryotic DNA replication and prokaryotic DNA replication?

Correct AnswerverifiedShow Answer

Which of the following cells do not have active telomerase activity?

Correct AnswerverifiedShow Answer

What is the difference between the leading strand and the lagging strand in DNA replication?

Correct AnswerverifiedShow Answer

Figure 14.3 -Refer to Figure 14.3.Which of the structures in the figure breaks hydrogen bonds between complementary bases?

Correct AnswerverifiedShow Answer

DNA is synthesized through a process known as _____.

Correct AnswerverifiedShow Answer

In a healthy cell,the rate of DNA repair is equal to the rate of DNA mutation.When the rate of repair lags behind the rate of mutation,what is a possible fate of the cell?

Correct AnswerverifiedShow Answer

DNA contains the template needed to copy itself,but as you learned in Chapter 4,it has no catalytic activity.What catalyzes the formation of phosphodiester bonds between adjacent nucleotides in the DNA polymer being formed?

Correct AnswerverifiedShow Answer

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