Question 1

DNA polymerase lengthens a polynucleotide strand by

Accepted Answer

A)  building short DNA fragments and linking them together. 
B)  adding lost DNA sequences to the 3' end. 
C)  linking purines with pyrimidines. 
D)  threading the existing DNA through a replication complex. 
E)  covalently linking new nucleotides to a previously existing strand. 
A)  building short DNA fragments and linking them together. 
B)  adding lost DNA sequences to the 3' end. 
C)  linking purines with pyrimidines. 
D)  threading the existing DNA through a replication complex. 
E)  covalently linking new nucleotides to a previously existing strand.

Question 2

In wild-type Drosophila melanogaster,the order of genes on a chromosome is yellow,vermillion,forked,and Bobbed.Some individuals have a different gene order: yellow,Bobbed,forked,and vermillion.The individuals with the altered gene order most likely have a(n)

Accepted Answer

A)  induced mutation. 
B)  point mutation. 
C)  reciprocal translocation. 
D)  conditional mutation. 
E)  chromosomal inversion. 
A)  induced mutation. 
B)  point mutation. 
C)  reciprocal translocation. 
D)  conditional mutation. 
E)  chromosomal inversion.

Question 3

You are studying DNA replication using a strain of yeast whose DNA polymerase is reported to have an error rate of 10-6 bases per cell cycle.However,your analyses of DNA sequences after DNA replication indicate that the error rate is closer to 10-10.What may explain your results?

Accepted Answer

A)  The yeast expresses high levels of DNA ligase. 
B)  The yeast has a mismatch repair system. 
C)  RNA polymerase has high fidelity. 
D)  The DNA polymerase can tolerate high temperatures. 
E)  The DNA polymerase is processive. 
A)  The yeast expresses high levels of DNA ligase. 
B)  The yeast has a mismatch repair system. 
C)  RNA polymerase has high fidelity. 
D)  The DNA polymerase can tolerate high temperatures. 
E)  The DNA polymerase is processive.

Question 4

The structure of DNA explains which three major properties of genes?

Accepted Answer

A)  They contain genetic information,direct the synthesis of proteins,and are contained in the cell nucleus. 
B)  They contain nitrogenous bases,direct the synthesis of RNA,and are contained in the cell nucleus. 
C)  They replicate exactly,are contained in the cell nucleus,and direct the synthesis of cellular proteins. 
D)  They contain genetic information,can replicate exactly,and are susceptible to stable mutations. 
E)  They encode the organism's phenotype,are passed on from one generation to the next,and contain nitrogenous bases. 
A)  They contain genetic information,direct the synthesis of proteins,and are contained in the cell nucleus. 
B)  They contain nitrogenous bases,direct the synthesis of RNA,and are contained in the cell nucleus. 
C)  They replicate exactly,are contained in the cell nucleus,and direct the synthesis of cellular proteins. 
D)  They contain genetic information,can replicate exactly,and are susceptible to stable mutations. 
E)  They encode the organism's phenotype,are passed on from one generation to the next,and contain nitrogenous bases.

Question 5

The ras gene encodes a protein that promotes cell division in response to growth factors.A gain-of-function point mutation in this gene would

Accepted Answer

A)  cause thymine to form covalent bonds with adjacent bases. 
B)  not cause a change in the amino acid sequence of the protein. 
C)  cause the protein to stop translation. 
D)  increase the probability that affected cells would become cancerous. 
E)  result in nondisjunction. 
A)  cause thymine to form covalent bonds with adjacent bases. 
B)  not cause a change in the amino acid sequence of the protein. 
C)  cause the protein to stop translation. 
D)  increase the probability that affected cells would become cancerous. 
E)  result in nondisjunction.

Question 6

If a mutation has a visible effect at 26°C but no visible effect at 20°C,then 20°C is the _______ temperature and 26°C is the _______ temperature.

Accepted Answer

A)  permissive;conditional 
B)  permissive;restrictive 
C)  restrictive;conditional 
D)  restrictive;permissive 
E)  conditional;restrictive 
A)  permissive;conditional 
B)  permissive;restrictive 
C)  restrictive;conditional 
D)  restrictive;permissive 
E)  conditional;restrictive

Question 7

Although DNA is made up of only four different bases,it can encode the information necessary to specify the workings of an entire organism.It can do this because DNA

Accepted Answer

A)  molecules are extremely long. 
B)  molecules are found in the nucleus. 
C)  is transcribed into RNA and then into proteins with specific functions. 
D)  is eventually translated into proteins,which are made up of 20 different amino acids. 
E)  uses the sugar deoxyribose. 
A)  molecules are extremely long. 
B)  molecules are found in the nucleus. 
C)  is transcribed into RNA and then into proteins with specific functions. 
D)  is eventually translated into proteins,which are made up of 20 different amino acids. 
E)  uses the sugar deoxyribose.

Question 8

Which statement about Okazaki fragments is true?

Accepted Answer

A)  They occur because DNA polymerase operates in only one direction along a strand of DNA. 
B)  They act as a primer that initiates DNA replication. 
C)  If they did not exist,the ends of chromosomes would get shorter with every replication. 
D)  It they did not exist,bases would pair with their complementary bases. 
E)  They reduce the mutation rate during DNA replication. 
A)  They occur because DNA polymerase operates in only one direction along a strand of DNA. 
B)  They act as a primer that initiates DNA replication. 
C)  If they did not exist,the ends of chromosomes would get shorter with every replication. 
D)  It they did not exist,bases would pair with their complementary bases. 
E)  They reduce the mutation rate during DNA replication.

Question 9

In PCR,_______ results in single-stranded DNA template molecules.

Accepted Answer

A)  heat 
B)  a high salt concentration 
C)  DNA polymerase 
D)  an exonuclease 
E)  a primer 
A)  heat 
B)  a high salt concentration 
C)  DNA polymerase 
D)  an exonuclease 
E)  a primer

Question 10

Silent mutations have no effect on amino acid sequences because

Accepted Answer

A)  silent mutations are usually found in noncoding regions of DNA. 
B)  the genetic code is ambiguous. 
C)  silent mutations are recessive,and the presence of the dominant allele will result in a functional protein. 
D)  silent mutations are conditional mutagens,and their phenotypes are altered only under very restrictive conditions. 
E)  only a single base is involved in a series of thousands of nucleotides. 
A)  silent mutations are usually found in noncoding regions of DNA. 
B)  the genetic code is ambiguous. 
C)  silent mutations are recessive,and the presence of the dominant allele will result in a functional protein. 
D)  silent mutations are conditional mutagens,and their phenotypes are altered only under very restrictive conditions. 
E)  only a single base is involved in a series of thousands of nucleotides.

Question 11

Why is RNA incorporated into the DNA molecule during DNA replication?

Accepted Answer

A)  DNA polymerases can only add on to an existing strand. 
B)  RNA primase is able to use DNA as a template. 
C)  RNA primase must be incorporated into the holoenzyme complex. 
D)  DNA polymerase first synthesizes RNA. 
E)  RNA serves as the template for DNA synthesis. 
A)  DNA polymerases can only add on to an existing strand. 
B)  RNA primase is able to use DNA as a template. 
C)  RNA primase must be incorporated into the holoenzyme complex. 
D)  DNA polymerase first synthesizes RNA. 
E)  RNA serves as the template for DNA synthesis.

Question 12

The strands that make up DNA are antiparallel.This means that

Accepted Answer

A)  one strand is positively charged,and the other is negatively charged. 
B)  the base pairings create unequal spacing between the two DNA strands. 
C)  the 5'-to-3'direction of one strand runs opposite to the 5'-to-3' direction of the other strand. 
D)  the twisting of the DNA molecule has shifted the two strands. 
E)  purines bond with purines and pyrimidines bond with pyrimidines. 
A)  one strand is positively charged,and the other is negatively charged. 
B)  the base pairings create unequal spacing between the two DNA strands. 
C)  the 5'-to-3'direction of one strand runs opposite to the 5'-to-3' direction of the other strand. 
D)  the twisting of the DNA molecule has shifted the two strands. 
E)  purines bond with purines and pyrimidines bond with pyrimidines.

Question 13

The breaking and rejoining of chromosomes can lead to

Accepted Answer

A)  deletions. 
B)  duplications. 
C)  inversions. 
D)  translocations. 
E)  All of the above 
A)  deletions. 
B)  duplications. 
C)  inversions. 
D)  translocations. 
E)  All of the above

Question 14

Recall that two hydrogen bonds bind A and T,but three hydrogen bonds bind G and C.The stability of DNA is affected by the number of hydrogen bonds,with more bonds promoting more stability.Double-stranded DNA molecules that have greater stability require more heat to be broken into single strands.Which double-stranded DNA molecules would likely require the lowest temperature in PCR?

Accepted Answer

A)  A molecule with 16 percent A 
B)  A molecule with 23 percent G 
C)  A molecule with 30 percent C 
D)  A molecule with 35 percent T 
E)  More information is required to answer this question. 
A)  A molecule with 16 percent A 
B)  A molecule with 23 percent G 
C)  A molecule with 30 percent C 
D)  A molecule with 35 percent T 
E)  More information is required to answer this question.

Question 15

Purines include

Accepted Answer

A)  cytosine,uracil,and thymine. 
B)  adenine and cytosine. 
C)  adenine and thymine. 
D)  cytosine and thymine. 
E)  adenine and guanine. 
A)  cytosine,uracil,and thymine. 
B)  adenine and cytosine. 
C)  adenine and thymine. 
D)  cytosine and thymine. 
E)  adenine and guanine.

Question 16

Recall that two hydrogen bonds bind A and T,but three hydrogen bonds bind G and C.Because the stability of DNA is affected by the number of hydrogen bonds,with more bonds promoting more stability,which double-stranded DNA molecule would likely have the greatest stability?

Accepted Answer

A)  A molecule with 20 percent A 
B)  A molecule with 26 percent G 
C)  A molecule with 32 percent C 
D)  A molecule with 38 percent T 
E)  More information is required to answer this question. 
A)  A molecule with 20 percent A 
B)  A molecule with 26 percent G 
C)  A molecule with 32 percent C 
D)  A molecule with 38 percent T 
E)  More information is required to answer this question.

Question 17

Which event does not occur during DNA replication?

Accepted Answer

A)  Unwinding of the parent double helix 
B)  Formation of short pieces that are connected by DNA ligase 
C)  Complementary base pairing 
D)  Use of a primer 
E)  Polymerization in the 3'-to-5' direction 
A)  Unwinding of the parent double helix 
B)  Formation of short pieces that are connected by DNA ligase 
C)  Complementary base pairing 
D)  Use of a primer 
E)  Polymerization in the 3'-to-5' direction

Question 18

Which statement about a eukaryotic DNA replication primer is true?

Accepted Answer

A)  It is a short strand of RNA added to the 3'end of the leading strand. 
B)  It is needed only once on a lagging strand. 
C)  It remains on the DNA after replication. 
D)  It ensures that there will be a free 5' end to which nucleotides can be added. 
E)  It is added to only one of the two template strands. 
A)  It is a short strand of RNA added to the 3'end of the leading strand. 
B)  It is needed only once on a lagging strand. 
C)  It remains on the DNA after replication. 
D)  It ensures that there will be a free 5' end to which nucleotides can be added. 
E)  It is added to only one of the two template strands.

Question 19

In what way does DNA replication differ in eukaryotes versus prokaryotes?

Accepted Answer

A)  In eukaryotes,synthesis of the new DNA strand is from 3' to 5',whereas in prokaryotes it is from 5' to 3'. 
B)  In eukaryotes,synthesis of the new DNA strand is from 5' to 3',whereas in prokaryotes it is from 3' to 5'. 
C)  There are many origins of replication in each eukaryotic chromosome and only one in bacterial DNA. 
D)  In eukaryotes,synthesis of the new DNA strand is from 5' to 3',whereas in prokaryotes it is random. 
E)  Okazaki fragments are produced in eukaryotic DNA replication but not in prokaryotic DNA replication. 
A)  In eukaryotes,synthesis of the new DNA strand is from 3' to 5',whereas in prokaryotes it is from 5' to 3'. 
B)  In eukaryotes,synthesis of the new DNA strand is from 5' to 3',whereas in prokaryotes it is from 3' to 5'. 
C)  There are many origins of replication in each eukaryotic chromosome and only one in bacterial DNA. 
D)  In eukaryotes,synthesis of the new DNA strand is from 5' to 3',whereas in prokaryotes it is random. 
E)  Okazaki fragments are produced in eukaryotic DNA replication but not in prokaryotic DNA replication.

Question 20

The enzyme DNA ligase is required continuously during DNA replication because

Accepted Answer

A)  fragments of the leading strand must be joined together. 
B)  fragments of the lagging strand must be joined together. 
C)  the parental strands must be joined back together. 
D)  3'-deoxynucleoside triphosphates must be converted to 5'-deoxynucleoside triphosphates. 
E)  the complex of proteins that work together at the replication fork must be prevented from falling apart. 
A)  fragments of the leading strand must be joined together. 
B)  fragments of the lagging strand must be joined together. 
C)  the parental strands must be joined back together. 
D)  3'-deoxynucleoside triphosphates must be converted to 5'-deoxynucleoside triphosphates. 
E)  the complex of proteins that work together at the replication fork must be prevented from falling apart.

Exam 9: DNA and Its Role in Heredity

DNA polymerase lengthens a polynucleotide strand by

In wild-type Drosophila melanogaster,the order of genes on a chromosome is yellow,vermillion,forked,and Bobbed.Some individuals have a different gene order: yellow,Bobbed,forked,and vermillion.The individuals with the altered gene order most likely have a(n)

You are studying DNA replication using a strain of yeast whose DNA polymerase is reported to have an error rate of 10-6 bases per cell cycle.However,your analyses of DNA sequences after DNA replication indicate that the error rate is closer to 10-10.What may explain your results?

The structure of DNA explains which three major properties of genes?

The ras gene encodes a protein that promotes cell division in response to growth factors.A gain-of-function point mutation in this gene would

If a mutation has a visible effect at 26°C but no visible effect at 20°C,then 20°C is the _______ temperature and 26°C is the _______ temperature.

Although DNA is made up of only four different bases,it can encode the information necessary to specify the workings of an entire organism.It can do this because DNA

Which statement about Okazaki fragments is true?

In PCR,_______ results in single-stranded DNA template molecules.

Silent mutations have no effect on amino acid sequences because

Why is RNA incorporated into the DNA molecule during DNA replication?

The strands that make up DNA are antiparallel.This means that

The breaking and rejoining of chromosomes can lead to

Purines include

Recall that two hydrogen bonds bind A and T,but three hydrogen bonds bind G and C.Because the stability of DNA is affected by the number of hydrogen bonds,with more bonds promoting more stability,which double-stranded DNA molecule would likely have the greatest stability?

Which event does not occur during DNA replication?

Which statement about a eukaryotic DNA replication primer is true?

In what way does DNA replication differ in eukaryotes versus prokaryotes?

The enzyme DNA ligase is required continuously during DNA replication because

Introduction

The Chemistry and Energy of Life

Nucleic Acids, Proteins, and Enzymes

Cells: the Working Units of Life

Cell Membranes and Signaling

Pathways That Harvest and Store Chemical Energy

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

From Dna to Protein: Gene Expression

Regulation of Gene Expression

Genomes

Biotechnology

Genes, Development, and Evolution

Processes of Evolution

Reconstructing and Using Phylogenies

Speciation

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

The Evolution of Plants

The Evolution and Diversity of Fungi

Animal Origins and Diversity

The Plant Body

Plant Nutrition and Transport

Plant Growth and Development

Reproduction of Flowering Plants

Plants in the Environment

Fundamentals of Animal Function

Nutrition and Digestion

Breathing

Circulation

Muscle and Movement

Neurons, Sense Organs, and Nervous Systems

Nervous and Endocrine Control

Water and Salts: Excretion

Animal Reproduction

Animal Development

Immunology: Animal Defense Systems

Animal Behavior

The Distribution of Earths Ecological Systems

Populations

Ecological and Evolutionary Consequences of Interactions Within and Among Species

Ecological Communities

The Global Ecosystem

Filters

You are studying DNA replication using a strain of yeast whose DNA polymerase is reported to have an error rate of 10^-⁶ bases per cell cycle.However,your analyses of DNA sequences after DNA replication indicate that the error rate is closer to 10^-¹⁰.What may explain your results?

If a mutation has a visible effect at 26°C but no visible effect at 20°C,then 20°C is the _ temperature and 26°C is the _ temperature.