Question 1

The comparison of the amino acid sequences of cytochrome c (see Figure 23.3) from plants to human showed that

Accepted Answer

A)  gaps were required in some cases to optimize the alignment. 
B)  there were very few invariant amino acids in the sequence. 
C)  the least variable regions were at the ends of the molecule. 
D)  there was little change in all parts of the molecule. 
E)  the amino acids with side chains that bind the heme were variable. 
A)  gaps were required in some cases to optimize the alignment. 
B)  there were very few invariant amino acids in the sequence. 
C)  the least variable regions were at the ends of the molecule. 
D)  there was little change in all parts of the molecule. 
E)  the amino acids with side chains that bind the heme were variable. A

Question 2

As the amount of lateral gene transfer in a taxon decreases, it becomes _______ difficult to infer relationships among lineages within the taxon and _______ to infer species boundaries.

Accepted Answer

A)  more; more difficult 
B)  more; less difficult 
C)  less; more difficult 
D)  less; there is no effect on the ability 
E)  less; less difficult 
A)  more; more difficult 
B)  more; less difficult 
C)  less; more difficult 
D)  less; there is no effect on the ability 
E)  less; less difficult E

Question 3

A molecular evolutionist wants to study the dynamics of in vitro evolution for a particular gene.Which model system would be optimal for the experiment?

Accepted Answer

A)  RNA virus 
B)  DNA virus 
C)  bacterium 
D)  mouse cell line 
E)  fruit fly cell line 
A)  RNA virus 
B)  DNA virus 
C)  bacterium 
D)  mouse cell line 
E)  fruit fly cell line A

Question 4

The rate of fixation of neutral mutations, , is

Accepted Answer

A)  independent of population size. 
B)  higher in small populations than in large populations. 
C)  higher in large populations than in small populations. 
D)  slower than the rate of fixation of deleterious mutations. 
E)  None of the above 
A)  independent of population size. 
B)  higher in small populations than in large populations. 
C)  higher in large populations than in small populations. 
D)  slower than the rate of fixation of deleterious mutations. 
E)  None of the above

Question 5

Which statement about the globin family is false?

Accepted Answer

A)  Hemoglobin has a higher affinity for oxygen than myoglobin does. 
B)  Myoglobin is the primary oxygen storage molecule in the muscles. 
C)  Hemoglobin and myoglobin have evolved to have somewhat different functions. 
D)  Hemoglobin has a tetrameric structure that allows it to carry more oxygen molecules than myoglobin does. 
E)  Myoglobin functions as a dimer. 
A)  Hemoglobin has a higher affinity for oxygen than myoglobin does. 
B)  Myoglobin is the primary oxygen storage molecule in the muscles. 
C)  Hemoglobin and myoglobin have evolved to have somewhat different functions. 
D)  Hemoglobin has a tetrameric structure that allows it to carry more oxygen molecules than myoglobin does. 
E)  Myoglobin functions as a dimer.

Question 6

Which statement about synonymous substitutions is false?

Accepted Answer

A)  They do not change the amino acid sequence of the protein. 
B)  They are the same as silent substitutions. 
C)  They generally evolve at a faster rate than nonsynonymous substitutions. 
D)  They are less likely to be influenced by natural selection than nonsynonymous substitutions are. 
E)  They change the amino acid sequence of the protein. 
A)  They do not change the amino acid sequence of the protein. 
B)  They are the same as silent substitutions. 
C)  They generally evolve at a faster rate than nonsynonymous substitutions. 
D)  They are less likely to be influenced by natural selection than nonsynonymous substitutions are. 
E)  They change the amino acid sequence of the protein.

Question 7

The occurrence of which event(s) usually does not lead to an undercounting of the real number of substitutions?

Accepted Answer

A)  Parallel substitutions 
B)  Back substitution 
C)  Single substitution 
D)  Multiple substitutions 
E)  Coincident substitutions 
A)  Parallel substitutions 
B)  Back substitution 
C)  Single substitution 
D)  Multiple substitutions 
E)  Coincident substitutions

Question 8

A change from _______ is a reversion.

Accepted Answer

A)  A to G 
B)  C to T 
C)  G to A 
D)  G to T 
E)  A to G and then back to A 
A)  A to G 
B)  C to T 
C)  G to A 
D)  G to T 
E)  A to G and then back to A

Question 9

According to the neutral theory of molecular evolution, the fastest rate of fixation of neutral mutations by genetic drift should occur in a population of _______ individuals.

Accepted Answer

A)  200 
B)  400 
C)  1,000 
D)  10,000 
E)  None of the above; the rates should be roughly the same for all. 
A)  200 
B)  400 
C)  1,000 
D)  10,000 
E)  None of the above; the rates should be roughly the same for all.

Question 10

Assume there is an influenza zoonotic (the equivalent of a pandemic, in nonhuman animals) occurring among pigs.Researchers use evolutionary analysis of recent swine, horse, bird, and human influenza outbreaks and determine that a _______ has occurred from humans to pigs.

Accepted Answer

cross-spec

Question 11

A biologist is examining species of plants found in Thailand in the hope of finding a naturally occurring treatment for cancer.This project is an example of

Accepted Answer

A)  the application of the principles of concerted evolution. 
B)  bioinformatics. 
C)  bioremediation. 
D)  bioprospecting. 
E)  the application of the principles of convergent evolution. 
A)  the application of the principles of concerted evolution. 
B)  bioinformatics. 
C)  bioremediation. 
D)  bioprospecting. 
E)  the application of the principles of convergent evolution.

Question 12

A researcher is interested in determining what nucleotide substitutions in TTX-resistant puffer fish sodium channels are critical for resistance.To facilitate her research, she uses PCR-based in vitro evolution to generate altered versions of the puffer fish sodium channels.To increase the possibility of generating genes that are not resistant to TTX, the researcher should

Accepted Answer

A)  use a DNA polymerase that has low fidelity. 
B)  not denature the DNA in between PCR cycles. 
C)  use DNA from other species of fish. 
D)  use DNA only from puffer fish that do not produce TTX. 
E)  limit the rounds of PCR to less than six. 
A)  use a DNA polymerase that has low fidelity. 
B)  not denature the DNA in between PCR cycles. 
C)  use DNA from other species of fish. 
D)  use DNA only from puffer fish that do not produce TTX. 
E)  limit the rounds of PCR to less than six.

Question 13

To create new antibiotics, biologists are taking advantage of the principles of evolution by using polymerase chain reaction (PCR) technology to copy DNA.This is an example of _______ evolution.

Accepted Answer

The answer of To create new antibiotics, biologists are taking...

Question 14

Researchers suspect that the gene FOXP2, which is involved in speech and cognition, has been under positive selection in the human lineage.Which of the following would provide the strongest support for such a claim?

Accepted Answer

A)  The gene shows evidence of bioprospecting. 
B)  There is a higher rate of nonsynonymous substitutions than of synonymous ones. 
C)  There is a lower rate of nonsynonymous substitutions than of synonymous ones. 
D)  The gene evolves following the molecular clock. 
E)  There have been more transitions than transversions in the gene. 
A)  The gene shows evidence of bioprospecting. 
B)  There is a higher rate of nonsynonymous substitutions than of synonymous ones. 
C)  There is a lower rate of nonsynonymous substitutions than of synonymous ones. 
D)  The gene evolves following the molecular clock. 
E)  There have been more transitions than transversions in the gene.

Question 15

Which statement about a genome is false?

Accepted Answer

A)  The genome must be replicated to be transmitted from parents to offspring. 
B)  Mutations can occur in the genome as a result of errors in DNA replication. 
C)  The genome is essentially a random collection of genes arranged in a random order along chromosomes. 
D)  In addition to the nuclear DNA, the genome also includes the DNA present in chloroplasts and mitochondria. 
E)  The positions of genes are subject to evolutionary change. 
A)  The genome must be replicated to be transmitted from parents to offspring. 
B)  Mutations can occur in the genome as a result of errors in DNA replication. 
C)  The genome is essentially a random collection of genes arranged in a random order along chromosomes. 
D)  In addition to the nuclear DNA, the genome also includes the DNA present in chloroplasts and mitochondria. 
E)  The positions of genes are subject to evolutionary change.

Question 16

A researcher is studying a metabolic disorder.To identify the gene or genes linked with the disorder's phenotype, he compares the chromosomal DNA of normal volunteers and clinical patients.Despite a great deal of work, he is unable to identify a gene.Another research group, however, reports a gene.Which of the following may account for the researcher's experimental failure?

Accepted Answer

A)  He analyzed too much DNA. 
B)  He should have only looked at the DNA of patients. 
C)  He did not analyze all of the genes found in a human cell. 
D)  He did not include chloroplast DNA. 
E)  Genes cannot be identified using this method. 
A)  He analyzed too much DNA. 
B)  He should have only looked at the DNA of patients. 
C)  He did not analyze all of the genes found in a human cell. 
D)  He did not include chloroplast DNA. 
E)  Genes cannot be identified using this method.

Question 17

Refer to the figure, which shows a phylogenetic tree of the engrailed gene family.   Which gene is the most closely related ortholog of human En1?

Accepted Answer

A)  Zebrafish En1a 
B)  Chicken En1 
C)  Lamprey En 
D)  Chicken En2 
E)  Mouse En1 
A)  Zebrafish En1a 
B)  Chicken En1 
C)  Lamprey En 
D)  Chicken En2 
E)  Mouse En1

Question 18

Genes from many isolates of the influenza virus have been sequenced.In certain regions of the genome, nonsynonymous substitutions are much more frequent than synonymous substitutions.Which statement is the most likely explanation for this pattern?

Accepted Answer

A)  A great deal of genetic drift is taking place. 
B)  Most of the amino acid changes are neutral. 
C)  Strong purifying selection is acting on these genes. 
D)  Strong positive selection is acting on these genes. 
E)  Mutations that change the amino acid are disadvantageous. 
A)  A great deal of genetic drift is taking place. 
B)  Most of the amino acid changes are neutral. 
C)  Strong purifying selection is acting on these genes. 
D)  Strong positive selection is acting on these genes. 
E)  Mutations that change the amino acid are disadvantageous.

Question 19

Over evolutionary history, many groups of organisms that inhabit caves have lost the organs of sight.For instance, although surface-dwelling crayfishes have functional eyes, several crayfish species that are restricted to underground habitats lack eyes.Opsins are a group of light-sensitive proteins known to have an important function in vision (see Chapter 45), and opsin genes are expressed in eye tissues.Opsin genes are present in the genomes of eyeless, cave-dwelling crayfishes.Two alternative hypotheses that might explain the presence of opsin genes in an eyeless organism are: (1) the genes are no longer experiencing purifying selection because there is no longer selection for function in vision; and (2) the genes are experiencing selection for a function other than vision.How would you investigate these two hypotheses, using the sequences of the opsin genes in various species of crayfishes?

Accepted Answer

This problem can be investigated by sequ

Question 20

Refer to the figure, which shows a phylogenetic tree of the engrailed gene family.   In the evolution timeline, which gene is the most recent paralog of zebrafish En2b?

Accepted Answer

A)  Zebrafish En2a 
B)  Chicken En2 
C)  Lamprey En 
D)  Sea urchin En 
E)  Human En1 
A)  Zebrafish En2a 
B)  Chicken En2 
C)  Lamprey En 
D)  Sea urchin En 
E)  Human En1

Exam 23: Evolution of Genes and Genomes

The comparison of the amino acid sequences of cytochrome c (see Figure 23.3) from plants to human showed that

As the amount of lateral gene transfer in a taxon decreases, it becomes _______ difficult to infer relationships among lineages within the taxon and _______ to infer species boundaries.

A molecular evolutionist wants to study the dynamics of in vitro evolution for a particular gene.Which model system would be optimal for the experiment?

The rate of fixation of neutral mutations, , is

Which statement about the globin family is false?

Which statement about synonymous substitutions is false?

The occurrence of which event(s) usually does not lead to an undercounting of the real number of substitutions?

A change from _______ is a reversion.

According to the neutral theory of molecular evolution, the fastest rate of fixation of neutral mutations by genetic drift should occur in a population of _______ individuals.

Assume there is an influenza zoonotic (the equivalent of a pandemic, in nonhuman animals) occurring among pigs.Researchers use evolutionary analysis of recent swine, horse, bird, and human influenza outbreaks and determine that a _______ has occurred from humans to pigs.

A biologist is examining species of plants found in Thailand in the hope of finding a naturally occurring treatment for cancer.This project is an example of

To create new antibiotics, biologists are taking advantage of the principles of evolution by using polymerase chain reaction (PCR) technology to copy DNA.This is an example of _______ evolution.

Researchers suspect that the gene FOXP2, which is involved in speech and cognition, has been under positive selection in the human lineage.Which of the following would provide the strongest support for such a claim?

Which statement about a genome is false?

Refer to the figure, which shows a phylogenetic tree of the engrailed gene family. Which gene is the most closely related ortholog of human En1?

Genes from many isolates of the influenza virus have been sequenced.In certain regions of the genome, nonsynonymous substitutions are much more frequent than synonymous substitutions.Which statement is the most likely explanation for this pattern?

Refer to the figure, which shows a phylogenetic tree of the engrailed gene family. In the evolution timeline, which gene is the most recent paralog of zebrafish En2b?

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Cell Communication and Multicellularity

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Animal Development

Neurons, Glia, and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Functions

Musculoskeletal Systems

Gas Exchange

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen Excretion

Animal Behavior

The Physical Environment and Biogeography of Life

Populations

Species Interactions

Communities

Ecosystems

A Changing Biosphere

Filters

As the amount of lateral gene transfer in a taxon decreases, it becomes _ difficult to infer relationships among lineages within the taxon and _ to infer species boundaries.