Question 1

Which one of the following is least likely to cause mutations in DNA?

Accepted Answer

A)  ultraviolet radiation from sunlight 
B)  aflatoxins that are found in mouldy grains 
C)  hydroxyl radicals formed as by- products of aerobic respiration 
D)  medical X- rays to detect broken bones 
E)  light from an incandescent bulb 
A)  ultraviolet radiation from sunlight 
B)  aflatoxins that are found in mouldy grains 
C)  hydroxyl radicals formed as by- products of aerobic respiration 
D)  medical X- rays to detect broken bones 
E)  light from an incandescent bulb E

Question 2

The epsilon s) 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 excises a segment of DNA around the mismatched base. 
B)  The epsilon subunit can remove a mismatched nucleotide. 
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. 
A)  The epsilon subunit excises a segment of DNA around the mismatched base. 
B)  The epsilon subunit can remove a mismatched nucleotide. 
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. B

Question 3

What appears to be a dark side to telomerase activity with regard to human health?

Accepted Answer

A)  Telomerase is active in most cancer cells. 
B)  Telomerase activity is only seen in somatic cells; therefore, chromosome shortening is likely in gametic chromosomes. 
C)  Telomerase is inhibited by p53. 
D)  There are more chromosomal ends than can be repaired by telomerase. 
E)  p53 inhibits telomerase. 
A)  Telomerase is active in most cancer cells. 
B)  Telomerase activity is only seen in somatic cells; therefore, chromosome shortening is likely in gametic chromosomes. 
C)  Telomerase is inhibited by p53. 
D)  There are more chromosomal ends than can be repaired by telomerase. 
E)  p53 inhibits telomerase. A

Question 4

Which of the following agents can cause mutations in DNA?

Accepted Answer

A)  ultraviolet radiation from sunlight 
B)  aflatoxins that are found in moldy grains 
C)  free radicals that are formed as by- products of aerobic respiration 
D)  All of the above are mutagenic agents. 
A)  ultraviolet radiation from sunlight 
B)  aflatoxins that are found in moldy grains 
C)  free radicals that are formed as by- products of aerobic respiration 
D)  All of the above are mutagenic agents.

Question 5

$\text {Single strand as a template plus $3 ^ { \prime }$ end to }$
$\text {start DNA synthesis}$

Figure 15.1
-Refer to Figure 15.1. What bases will be added to the primer as DNA replication proceeds? The bases should appear in the order that they will be added.

Accepted Answer

A)  A, G, A, C, G, A, C 
B)  T, C, T, G, C, T, G 
C)  C, A, G, C, A, G, A 
D)  U, G, U, C, G, U, C 
A)  A, G, A, C, G, A, C 
B)  T, C, T, G, C, T, G 
C)  C, A, G, C, A, G, A 
D)  U, G, U, C, G, U, C

Question 6

How does the simple primary and secondary structure of DNA hold the information needed to code for the many features of multicellular organisms?

Accepted Answer

A)  The hydrogen bonding among backbone constituents carries coded information. 
B)  The base sequence of DNA carries all the information needed to code for proteins. 
C)  The amino acids that make up the DNA molecule contain the information needed to make cellular proteins. 
D)  The covalent bonding among backbone constituents contains the information that is passed from generation to generation. 
A)  The hydrogen bonding among backbone constituents carries coded information. 
B)  The base sequence of DNA carries all the information needed to code for proteins. 
C)  The amino acids that make up the DNA molecule contain the information needed to make cellular proteins. 
D)  The covalent bonding among backbone constituents contains the information that is passed from generation to generation.

Question 7

What are thymine dimers?

Accepted Answer

A)  pyrimidines C and T) that have gained an extra nitrogen- containing ring structure 
B)  thymines on antiparallel DNA strands that form complementary base pairs 
C)  thymines formed by demethylation of purines 
D)  adjacent thymines on the same DNA strand that join by covalent bonding 
A)  pyrimidines C and T) that have gained an extra nitrogen- containing ring structure 
B)  thymines on antiparallel DNA strands that form complementary base pairs 
C)  thymines formed by demethylation of purines 
D)  adjacent thymines on the same DNA strand that join by covalent bonding

Question 8

Semiconservative replication involves a template. What is the template?

Accepted Answer

A)  an RNA molecule 
B)  one strand of the DNA molecule 
C)  DNA polymerase contains the template needed 
D)  single- stranded binding proteins 
A)  an RNA molecule 
B)  one strand of the DNA molecule 
C)  DNA polymerase contains the template needed 
D)  single- stranded binding proteins

Question 9

Telomere shortening is a problem in which types of cells?

Accepted Answer

A)  prokaryotes 
B)  eukaryotes 
C)  both prokaryotes and eukaryotes 
A)  prokaryotes 
B)  eukaryotes 
C)  both prokaryotes and eukaryotes

Question 10

If during the process of DNA replication, the enzyme topoisomerase was not functioning i.e. it was mutated) what do you expect will happen to the replication process?

Accepted Answer

A)  The double helix would unwind completely but no primers would be added to the template strand. 
B)  The double helix would unwind completely but no new strand would be created due to the formation of secondary structures. 
C)  The double helix would begin to unwind but this unwinding would stop prematurely due to over- twisting of the DNA. 
D)  The double helix would not begin to unwind at all. 
A)  The double helix would unwind completely but no primers would be added to the template strand. 
B)  The double helix would unwind completely but no new strand would be created due to the formation of secondary structures. 
C)  The double helix would begin to unwind but this unwinding would stop prematurely due to over- twisting of the DNA. 
D)  The double helix would not begin to unwind at all.

Question 11

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

Question 12

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 repair of pyrimidine dimers 
B)  increased rate of errors by wild- type DNA polymerase 
C)  decreased ability to repair certain DNA mutations 
D)  increased rate of formation of pyrimidine dimers 
A)  increased rate of repair of pyrimidine dimers 
B)  increased rate of errors by wild- type DNA polymerase 
C)  decreased ability to repair certain DNA mutations 
D)  increased rate of formation of pyrimidine dimers

Question 13

What can you infer from the information presented in this table?

Accepted Answer

A)  DNA polymerase I and DNA polymerase III have different functions. 
B)  The sliding clamp molecule is a ribozyme. 
C)  DNA polymerase I and DNA polymerase III are the same enzyme found in different organisms. 
D)  Topoisomerase is involved in proofreading activity. 
A)  DNA polymerase I and DNA polymerase III have different functions. 
B)  The sliding clamp molecule is a ribozyme. 
C)  DNA polymerase I and DNA polymerase III are the same enzyme found in different organisms. 
D)  Topoisomerase is involved in proofreading activity.

Question 14

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

Accepted Answer

A)  Meselson and Stahl 
B)  Hershey and Chase 
C)  Watson and Crick 
D)  Franklin and Wilkins 
A)  Meselson and Stahl 
B)  Hershey and Chase 
C)  Watson and Crick 
D)  Franklin and Wilkins

Question 15

The transduction experiments done by Hershey and Chase, and the transformation experiments done by Griffith, supported the same conclusion, which was that

Accepted Answer

A)  genetic recombination in living organisms is rare. 
B)  organisms must be sacrificed for science to progress. 
C)  pathogenic molecules affect the health of all living organisms. 
D)  DNA is the molecular substance of genetic inheritance. 
A)  genetic recombination in living organisms is rare. 
B)  organisms must be sacrificed for science to progress. 
C)  pathogenic molecules affect the health of all living organisms. 
D)  DNA is the molecular substance of genetic inheritance.

Question 16

Which of the following would you expect of a eukaryote lacking telomerase?

Accepted Answer

A)  a high probability of somatic cells becoming cancerous 
B)  high sensitivity to sunlight 
C)  a reduction in chromosome length in gametes 
D)  an inability to produce Okazaki fragments 
E)  an inability to repair thymine dimers 
A)  a high probability of somatic cells becoming cancerous 
B)  high sensitivity to sunlight 
C)  a reduction in chromosome length in gametes 
D)  an inability to produce Okazaki fragments 
E)  an inability to repair thymine dimers

Question 17

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

Question 18

Put the following steps of DNA replication in chronological order.
1) Single- stranded binding proteins attach to DNA strands.
2) Hydrogen bonds between base pairs of antiparallel strands are broken.
3) Primase binds to the site of origin.
4) DNA polymerase binds to the template strand.
5) An RNA primer is created.

Accepted Answer

A)  3, 2, 1, 5, 4 
B)  1, 2, 3, 4, 4 
C)  2, 1, 3, 5, 4 
D)  1, 2, 3, 4, 5 
A)  3, 2, 1, 5, 4 
B)  1, 2, 3, 4, 4 
C)  2, 1, 3, 5, 4 
D)  1, 2, 3, 4, 5

Question 19

The fact that within a double- stranded DNA molecule, adenine forms two hydrogen bonds with thymine and cytosine forms three hydrogen bonds with guanine is known as

Accepted Answer

A)  a double helix. 
B)  complementary base pairing. 
C)  semi- conservative replication. 
D)  secondary structure of a DNA molecule. 
A)  a double helix. 
B)  complementary base pairing. 
C)  semi- conservative replication. 
D)  secondary structure of a DNA molecule.

Question 20

Figure 15.3
-Refer to Figure 15.3. Which of the structures in the figure breaks hydrogen bonds between complementary bases?

Accepted Answer

The answer of   Figure 15.3
-Refer to Figure 15.3....

Exam 15: Dna and the Gene: Synthesis and Repair

Which one of the following is least likely to cause mutations in DNA?

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

What appears to be a dark side to telomerase activity with regard to human health?

Which of the following agents can cause mutations in DNA?

\text {Single strand as a template plus 3 ^ { \prime } end to } start DNA synthesis\text {start DNA synthesis}start DNA synthesis Figure 15.1 -Refer to Figure 15.1. What bases will be added to the primer as DNA replication proceeds? The bases should appear in the order that they will be added.

How does the simple primary and secondary structure of DNA hold the information needed to code for the many features of multicellular organisms?

What are thymine dimers?

Semiconservative replication involves a template. What is the template?

Telomere shortening is a problem in which types of cells?

If during the process of DNA replication, the enzyme topoisomerase was not functioning i.e. it was mutated) what do you expect will happen to the replication process?

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?

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?

What can you infer from the information presented in this table?

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

The transduction experiments done by Hershey and Chase, and the transformation experiments done by Griffith, supported the same conclusion, which was that

Which of the following would you expect of a eukaryote lacking telomerase?

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

The fact that within a double- stranded DNA molecule, adenine forms two hydrogen bonds with thymine and cytosine forms three hydrogen bonds with guanine is known as

Figure 15.3 -Refer to Figure 15.3. Which of the structures in the figure breaks hydrogen bonds between complementary bases?

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Lipids, Membranes, and the First Cells

Inside the Cell

Energy and Enzymes

Cellular Respiration and Fermentation

Photosynthesis

Cellcell Interactions

The Cell Cycle

Meiosis

Mendel and the Gene

How Genes Work

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

The Molecular Revolution: Biotechnology and Beyond

Gene Structure and Development

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Nervous Systems

Animal Sensory Systems

Animal Movement

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioural Ecology

Population Ecology

Community Ecology

Ecosystems and Global Ecology

Biodiversity and Conservation Biology

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