Question 1

Which statement CORRECTLY describes why the DNA synthesis is discontinuous on one template strand while continuous on the other? (Select all that apply.)

Accepted Answer

A)  It is due to antiparallel nature of the DNA molecule. 
B)  It is due to the fact that the DNA polymerase is not active enough. 
C)  It is due to the nature of the DNA polymerase which can only add new nucleotide at the 3ʹ end. 
D)  It is due to difficulty in unwinding the DNA template for replication. 
E)  It is due to the semiconservative nature of DNA replication. 
A)  It is due to antiparallel nature of the DNA molecule. 
B)  It is due to the fact that the DNA polymerase is not active enough. 
C)  It is due to the nature of the DNA polymerase which can only add new nucleotide at the 3ʹ end. 
D)  It is due to difficulty in unwinding the DNA template for replication. 
E)  It is due to the semiconservative nature of DNA replication.

Question 2

What type of bonds does DNA ligase create between adjacent nucleotides?

Accepted Answer

A)  hydrogen 
B)  phosphodiester 
C)  ionic 
D)  metallic 
E)  ribonucleotide 
A)  hydrogen 
B)  phosphodiester 
C)  ionic 
D)  metallic 
E)  ribonucleotide

Question 3

What does the term "noncrossover recombinant" mean with respect to homologous recombination?

Accepted Answer

The term "noncrossover recombinant" refe

Question 4

The radioactive labeling experiment similar to Meselson and Stahl's experiment was performed to determine what happens to histone proteins in eukaryotic DNA replication. Preexisting and newly synthesized histone proteins were labeled with radioactive isotopes of different atomic mass. Select the statement(s) that are consistent with the diagram shown. (Select all that apply.)

Accepted Answer

A)  The newly synthesized histone and preexisting histones exist separately and associate with a different pool of DNA. 
B)  The newly synthesized histone and preexisting histones mix and form smeared bands, representing heterogeneous mixture. 
C)  The newly synthesized histone only associates with newly synthesized DNA while the preexisting histone associates with the old DNA. 
D)  The newly synthesized histone and preexisting histones tend to mix together and reassociate with DNA after each round of the replication. 
E)  The preexisting histones tend to associate with newly synthesized DNA while the newly synthesized histone associates exclusively with the old DNA. 
A)  The newly synthesized histone and preexisting histones exist separately and associate with a different pool of DNA. 
B)  The newly synthesized histone and preexisting histones mix and form smeared bands, representing heterogeneous mixture. 
C)  The newly synthesized histone only associates with newly synthesized DNA while the preexisting histone associates with the old DNA. 
D)  The newly synthesized histone and preexisting histones tend to mix together and reassociate with DNA after each round of the replication. 
E)  The preexisting histones tend to associate with newly synthesized DNA while the newly synthesized histone associates exclusively with the old DNA.

Question 5

Summarize the similarities and differences in rolling-circle replication, theta replication, and linear eukaryotic replication.

Accepted Answer

Rolling-circle replication, theta replic

Question 6

Which different DNA polymerases are found in eukaryotic cells? What are their functions?

Accepted Answer

Eukaryotic cells contain several differe

Question 7

Okazaki fragments are found in all of the following EXCEPT in:

Accepted Answer

A)  the leading strand. 
B)  the lagging strand. 
C)  eukaryotic DNA. 
D)  bacterial DNA. 
E)  linear replication models. 
A)  the leading strand. 
B)  the lagging strand. 
C)  eukaryotic DNA. 
D)  bacterial DNA. 
E)  linear replication models.

Question 8

Which of the following is a necessary step in the Holliday model of recombination?

Accepted Answer

A)  DNA primase generates an RNA primer. 
B)  The RNA template of telomerase binds to the telomere. 
C)  Topoisomerases aid in supercoiling. 
D)  DNA polymerase $\alpha$ initiates DNA synthesis. 
E)  A single-strand break occurs in the DNA molecule. 
A)  DNA primase generates an RNA primer. 
B)  The RNA template of telomerase binds to the telomere. 
C)  Topoisomerases aid in supercoiling. 
D)  DNA polymerase $\alpha$ initiates DNA synthesis. 
E)  A single-strand break occurs in the DNA molecule.

Question 9

What would be a likely result of expressing telomerase in somatic cells?

Accepted Answer

A)  premature aging 
B)  cancer 
C)  lower rates of replication 
D)  immortality of gametes 
E)  early termination of replication 
A)  premature aging 
B)  cancer 
C)  lower rates of replication 
D)  immortality of gametes 
E)  early termination of replication

Question 10

Use the following to answer questions 
The nuclear genome of a single human cell (i.e., the entire diploid complement) contains about 6.6 billion (6.6 × 10S1U1P19S1S1P0) base pairs of DNA. If synthesis at each replication fork occurs at an average rate of 50 nucleotides per second, all the DNA is replicated in 5 minutes. Assume that replication is initiated simultaneously at all origins.
-How many origins of replication exist in a human diploid genome?

Accepted Answer

A)  220,000 
B)  440,000 
C)  880,000 
D)  2.64 × 107 
E)  1.32 × 108 
A)  220,000 
B)  440,000 
C)  880,000 
D)  2.64 × 107 
E)  1.32 × 108

Question 11

In the diagram below, which letter indicates the 5'end of the leading strand?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  C and D 
A)  A 
B)  B 
C)  C 
D)  D 
E)  C and D

Question 12

The proofreading function of DNA polymerases involves _____ activity.

Accepted Answer

A)  5' $\rightarrow$3' exonuclease 
B)  3' $\rightarrow$ 5'exonuclease 
C)  5' $\rightarrow$ 3' telomerase 
D)  3' $\rightarrow$ 5' telomerase 
E)  5' $\rightarrow$ 3' gyrase 
A)  5' $\rightarrow$3' exonuclease 
B)  3' $\rightarrow$ 5'exonuclease 
C)  5' $\rightarrow$ 3' telomerase 
D)  3' $\rightarrow$ 5' telomerase 
E)  5' $\rightarrow$ 3' gyrase

Question 13

Use the following to answer questions 
The nuclear genome of a single human cell (i.e., the entire diploid complement) contains about 6.6 billion (6.6 × 10S1U1P19S1S1P0) base pairs of DNA. If synthesis at each replication fork occurs at an average rate of 50 nucleotides per second, all the DNA is replicated in 5 minutes. Assume that replication is initiated simultaneously at all origins.
-Assuming that the origins are approximately equally distributed across the chromosomes, what is the average number of origins per human chromosome?

Accepted Answer

A)  4783 
B)  19,130 
C)  4.6 × 106 
D)  1.21 × 109 
E)  2.9 × 1010 
A)  4783 
B)  19,130 
C)  4.6 × 106 
D)  1.21 × 109 
E)  2.9 × 1010

Question 14

If a deletion occurs in a gene that encodes DNA polymerase I and no functional DNA polymerase I is produced, what will be the MOST likely consequence of this mutation?

Accepted Answer

A)  The DNA strands would contain pieces of RNA. 
B)  The DNA would not exist in a supercoiled state. 
C)  There would be no DNA replication on the leading or lagging strands. 
D)  There would be no RNA primers laid down. 
E)  The DNA will not be able to unwind to initiate replication. 
A)  The DNA strands would contain pieces of RNA. 
B)  The DNA would not exist in a supercoiled state. 
C)  There would be no DNA replication on the leading or lagging strands. 
D)  There would be no RNA primers laid down. 
E)  The DNA will not be able to unwind to initiate replication.

Question 15

Meselson and Stahl showed that DNA is replicated by a:

Accepted Answer

A)  conservative system. 
B)  semiconservative system. 
C)  dispersive system. 
D)  semidispersive system. 
E)  conservative system in prokaryotes and dispersive system in eukaryotes. 
A)  conservative system. 
B)  semiconservative system. 
C)  dispersive system. 
D)  semidispersive system. 
E)  conservative system in prokaryotes and dispersive system in eukaryotes.

Question 16

_____ are tandemly repeated DNA sequences located at the ends of eukaryotic chromosomes.

Accepted Answer

A)  Replication bubbles 
B)  Telomeres 
C)  Nucleosomes 
D)  Licensing factors 
E)  Holliday junctions 
A)  Replication bubbles 
B)  Telomeres 
C)  Nucleosomes 
D)  Licensing factors 
E)  Holliday junctions

Question 17

All DNA polymerases synthesize new DNA by adding nucleotides to the _____ of the growing DNA chain.

Accepted Answer

A)  3' OH 
B)  5' OH 
C)  3'phosphate 
D)  5' phosphate 
E)  nitrogenous base 
A)  3' OH 
B)  5' OH 
C)  3'phosphate 
D)  5' phosphate 
E)  nitrogenous base

Question 18

Draw a replication fork and indicate all key components and orientations, including lagging and leading strands, DNA helicase, RNA primer, and DNA gyrase.

Accepted Answer

To draw a replication fork, start by dra

Question 19

Which of the following statements is TRUE regarding nucleosome formation during DNA replication?

Accepted Answer

A)  Nucleosomes are only reassembled on the lagging strand. 
B)  Nucleosome assembly consists entirely of newly synthesized histones. 
C)  Nucleosome assembly occurs at a faster rate in prokaryotes than in eukaryotes. 
D)  The addition of newly synthesized histones is a part of nucleosome assembly. 
E)  Nucleosome assembly does not occur during semiconservative replication. 
A)  Nucleosomes are only reassembled on the lagging strand. 
B)  Nucleosome assembly consists entirely of newly synthesized histones. 
C)  Nucleosome assembly occurs at a faster rate in prokaryotes than in eukaryotes. 
D)  The addition of newly synthesized histones is a part of nucleosome assembly. 
E)  Nucleosome assembly does not occur during semiconservative replication.

Question 20

Which of the following enzymes do NOT aid in the unwinding of DNA for replication?

Accepted Answer

A)  helicase 
B)  single-stranded binding proteins 
C)  primase 
D)  gyrase 
E)  topoisomerase 
A)  helicase 
B)  single-stranded binding proteins 
C)  primase 
D)  gyrase 
E)  topoisomerase

Exam 12: DNA Replication and Recombination

Which statement CORRECTLY describes why the DNA synthesis is discontinuous on one template strand while continuous on the other? (Select all that apply.)

What type of bonds does DNA ligase create between adjacent nucleotides?

What does the term "noncrossover recombinant" mean with respect to homologous recombination?

Summarize the similarities and differences in rolling-circle replication, theta replication, and linear eukaryotic replication.

Which different DNA polymerases are found in eukaryotic cells? What are their functions?

Okazaki fragments are found in all of the following EXCEPT in:

Which of the following is a necessary step in the Holliday model of recombination?

What would be a likely result of expressing telomerase in somatic cells?

In the diagram below, which letter indicates the 5'end of the leading strand?

The proofreading function of DNA polymerases involves _____ activity.

If a deletion occurs in a gene that encodes DNA polymerase I and no functional DNA polymerase I is produced, what will be the MOST likely consequence of this mutation?

Meselson and Stahl showed that DNA is replicated by a:

_____ are tandemly repeated DNA sequences located at the ends of eukaryotic chromosomes.

All DNA polymerases synthesize new DNA by adding nucleotides to the _____ of the growing DNA chain.

Draw a replication fork and indicate all key components and orientations, including lagging and leading strands, DNA helicase, RNA primer, and DNA gyrase.

Which of the following statements is TRUE regarding nucleosome formation during DNA replication?

Which of the following enzymes do NOT aid in the unwinding of DNA for replication?

Introduction to Genetics

Chromosomes and Cellular Reproduction

Basic Principles of Heredity

Sex Determination and Sex-Linked Characteristics

Extensions and Modifications of Basic Principles

Pedigree Analysis, Applications, and Genetic Testing

Linkage, Recombination, and Eukaryotic Gene Mapping

Chromosome Variation

Bacterial and Viral Genetic Systems

DNA: the Chemical Nature of the Gene

Chromosome Structure and Organelle Dna

Transcription

Rna Molecules and Rna Processing

The Genetic Code and Translation

Control of Gene Expression in Prokaryotes

Control of Gene Expression in Eukaryotes

Gene Mutations and Dna Repair

Molecular Genetic Analysis and Biotechnology

Genomics and Proteomics

Epigenetics

Developmental Genetics and Immunogenetics

Cancer Genetics

Quantitative Genetics

Population Genetics

Evolutionary Genetics

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