Question 1

Which statement is true?

Accepted Answer

A)  All orthologs are paralogs. 
B)  All paralogs are orthologs. 
C)  All homologs are orthologs. 
D)  All orthologs are homologs. 
E)  No homologs are orthologs. 
A)  All orthologs are paralogs. 
B)  All paralogs are orthologs. 
C)  All homologs are orthologs. 
D)  All orthologs are homologs. 
E)  No homologs are orthologs.

Question 2

According to the neutral theory of molecular evolution,

Accepted Answer

A)  most alleles found in natural populations are neutral. 
B)  nearly all mutations have some effect on the organism. 
C)  the rate of fixation of neutral mutations is much faster in small populations than it is in large ones. 
D)  molecular clocks do not work. 
E)  neutral mutations accumulate through genetic drift. 
A)  most alleles found in natural populations are neutral. 
B)  nearly all mutations have some effect on the organism. 
C)  the rate of fixation of neutral mutations is much faster in small populations than it is in large ones. 
D)  molecular clocks do not work. 
E)  neutral mutations accumulate through genetic drift.

Question 3

The tomato genome has about 32,000 functional genes.In comparison, the human genome contains about _______ as many.

Accepted Answer

A)  2/3 
B)  2 times 
C)  5 times 
D)  40 times 
E)  100 times 
A)  2/3 
B)  2 times 
C)  5 times 
D)  40 times 
E)  100 times

Question 4

Which scenario is not a likely occurrence after a gene duplication event?

Accepted Answer

A)  One gene retains its function, while the other becomes a pseudogene. 
B)  Both genes retain their functions, but they are expressed in different patterns or tissues. 
C)  Both genes become pseudogenes. 
D)  One gene retains its function, while the other evolves to have a new function. 
E)  Both genes are deleted from the genome. 
A)  One gene retains its function, while the other becomes a pseudogene. 
B)  Both genes retain their functions, but they are expressed in different patterns or tissues. 
C)  Both genes become pseudogenes. 
D)  One gene retains its function, while the other evolves to have a new function. 
E)  Both genes are deleted from the genome.

Question 5

In a sequence of DNA taken from various species of snails, researchers have found that the rates of nonsynonymous substitutions and synonymous substitutions are roughly the same.What can we infer from this pattern?

Accepted Answer

A)  Transversions are more common than transitions. 
B)  Most of the amino acid changes are neutral. 
C)  Strong purifying selection is acting on this gene. 
D)  Strong positive selection is acting on this gene. 
E)  This gene cannot be used as a molecular clock. 
A)  Transversions are more common than transitions. 
B)  Most of the amino acid changes are neutral. 
C)  Strong purifying selection is acting on this gene. 
D)  Strong positive selection is acting on this gene. 
E)  This gene cannot be used as a molecular clock.

Question 6

Which outcome results from the misalignment of highly repeated genes?

Accepted Answer

A)  Unequal crossing over 
B)  Biased gene conversion 
C)  Parallel substitutions 
D)  The production of paralogs 
E)  Transitions 
A)  Unequal crossing over 
B)  Biased gene conversion 
C)  Parallel substitutions 
D)  The production of paralogs 
E)  Transitions

Question 7

An evolutionary biologist is studying gene A.The biologist constructs a gene tree to see how it is related in various species.The gene tree reveals multiple copies of the gene in each species.Within each species the copies of gene A are homologous but not identical.These results indicate that the biologist has identified _______ of gene A that are related through gene duplication events.

Accepted Answer

The answer of An evolutionary biologist is studying gene A.The...

Question 8

Biologists use a chemical derived from a bacterium to help treat sewage waste.This is an example of

Accepted Answer

A)  in vitro evolution. 
B)  reverse transcriptase. 
C)  biased gene conversion. 
D)  bioprospecting. 
E)  remediation. 
A)  in vitro evolution. 
B)  reverse transcriptase. 
C)  biased gene conversion. 
D)  bioprospecting. 
E)  remediation.

Question 9

Copies of genes in the same or different species that are related as the result of gene duplications are known as

Accepted Answer

A)  analogs. 
B)  orthologs. 
C)  paralogs. 
D)  heterologs. 
E)  monologs. 
A)  analogs. 
B)  orthologs. 
C)  paralogs. 
D)  heterologs. 
E)  monologs.

Question 10

Transitions, which are changes from _______, occur _______ transversions.

Accepted Answer

A)  purines to purines or pyrimidines to pyrimidines; more often than 
B)  purines to purines or pyrimidines to pyrimidines; about as frequently as 
C)  purines to purines or pyrimidines to pyrimidines; less often than 
D)  purines to pyrimidines or pyrimidines to purines; more often than 
E)  purines to pyrimidines or pyrimidines to purines; less often than 
A)  purines to purines or pyrimidines to pyrimidines; more often than 
B)  purines to purines or pyrimidines to pyrimidines; about as frequently as 
C)  purines to purines or pyrimidines to pyrimidines; less often than 
D)  purines to pyrimidines or pyrimidines to purines; more often than 
E)  purines to pyrimidines or pyrimidines to purines; less often than

Question 11

Changes to _______ will not affect the phenotype of an organism.

Accepted Answer

A)  the nucleotide sequence of DNA that codes for protein 
B)  the positions of coding genes 
C)  the extent of noncoding DNA 
D)  the location of noncoding DNA 
E)  a codon that does not alter the encoded amino acid 
A)  the nucleotide sequence of DNA that codes for protein 
B)  the positions of coding genes 
C)  the extent of noncoding DNA 
D)  the location of noncoding DNA 
E)  a codon that does not alter the encoded amino acid

Question 12

Which statement about about noncoding DNA is true?

Accepted Answer

A)  Selection against the accumulation of noncoding DNA is more effective in species with small populations. 
B)  Noncoding sequences are thought to be slightly advantageous. 
C)  Large genomes can slow down the rates of a growing organism. 
D)  Noncoding DNA accumulates at the same rate in all species. 
E)  Noncoding DNA accumulates more quickly in species with large population sizes. 
A)  Selection against the accumulation of noncoding DNA is more effective in species with small populations. 
B)  Noncoding sequences are thought to be slightly advantageous. 
C)  Large genomes can slow down the rates of a growing organism. 
D)  Noncoding DNA accumulates at the same rate in all species. 
E)  Noncoding DNA accumulates more quickly in species with large population sizes.

Question 13

Two species of plants that diverged 25 million years ago have accumulated an estimated 18 nucleotide differences in a gene.Species A has an average population size of 2 million, while species B has an average population size of 0.8 million.Both of these plants are annuals, with one generation per year.Assuming that the substitutions are all neutral, the estimated neutral mutation rate for this gene is _______ per million generations.

Accepted Answer

The answer of Two species of plants that diverged 25...

Question 14

In order to estimate the age of the split between the globin gene clusters, scientists did which of the following?

Accepted Answer

A)  Only examined the fossil record 
B)  Only constructed a molecular clock analysis 
C)  Examined the ratio of nonsynonymous to synonymous substitution rates 
D)  Both examined the fossil record and constructed a molecular clock analysis 
E)  Examined the ratio of functional genes to pseudogenes 
A)  Only examined the fossil record 
B)  Only constructed a molecular clock analysis 
C)  Examined the ratio of nonsynonymous to synonymous substitution rates 
D)  Both examined the fossil record and constructed a molecular clock analysis 
E)  Examined the ratio of functional genes to pseudogenes

Question 15

Which statement about synonymous mutations is true?

Accepted Answer

A)  They change the amino acid composition of the protein. 
B)  They can occur because of the redundancy of the genetic code. 
C)  They will affect the structure of the protein. 
D)  They usually evolve more slowly than nonsynonymous substitutions. 
E)  They will likely be lethal. 
A)  They change the amino acid composition of the protein. 
B)  They can occur because of the redundancy of the genetic code. 
C)  They will affect the structure of the protein. 
D)  They usually evolve more slowly than nonsynonymous substitutions. 
E)  They will likely be lethal.

Question 16

Refer to figure.   A researcher compares the sequences of a specific gene from various primate species.At nucleotide position 687 of this gene, all but two of the primates have a cytosine: the human has adenine, and the lemur has guanine at this position.This is evidence that the nucleotide substitutions at position 687 in humans and chimpanzees are most likely an example of

Accepted Answer

A)  a transversion. 
B)  reversion. 
C)  multiple substitutions. 
D)  coincident substitutions. 
E)  back substitutions. 
A)  a transversion. 
B)  reversion. 
C)  multiple substitutions. 
D)  coincident substitutions. 
E)  back substitutions.

Question 17

A number of genes that evolved from duplications of an ancestral gene now code for odor receptors in Drosophila.These odor receptor genes thus comprise a gene

Accepted Answer

A)  tree. 
B)  family. 
C)  pool. 
D)  assemblage. 
E)  network. 
A)  tree. 
B)  family. 
C)  pool. 
D)  assemblage. 
E)  network.

Question 18

Molecular evolutionists are able to study evolution directly using research models such as viruses, bacteria, and unicellular eukaryotes because substitution rates are related to _______ rather than to _______.

Accepted Answer

A)  size of genome; size of noncoding DNA 
B)  generation time; absolute time 
C)  a gene's sequence length; it's nucleotide composition 
D)  absolute time; generation time 
E)  size of noncoding DNA; size of genome 
A)  size of genome; size of noncoding DNA 
B)  generation time; absolute time 
C)  a gene's sequence length; it's nucleotide composition 
D)  absolute time; generation time 
E)  size of noncoding DNA; size of genome

Question 19

Biased gene conversion is a mechanism of _______ wherein copy number _______.

Accepted Answer

A)  lateral gene transfer; is maintained 
B)  lateral gene transfer; can change 
C)  in vitro evolution; can change 
D)  concerted evolution; is maintained 
E)  concerted evolution; can change 
A)  lateral gene transfer; is maintained 
B)  lateral gene transfer; can change 
C)  in vitro evolution; can change 
D)  concerted evolution; is maintained 
E)  concerted evolution; can change

Question 20

Refer to the table and sequence.   If C were substituted for the nucleotide in position 4 (highlighted) of the sequence, this would be characterized as a _______ nucleotide substitution.

Accepted Answer

A)  nonsynonymous 
B)  synonymous 
C)  deleterious 
D)  missense 
E)  nonsense 
A)  nonsynonymous 
B)  synonymous 
C)  deleterious 
D)  missense 
E)  nonsense

Exam 23: Evolution of Genes and Genomes

Which statement is true?

According to the neutral theory of molecular evolution,

The tomato genome has about 32,000 functional genes.In comparison, the human genome contains about _______ as many.

Which scenario is not a likely occurrence after a gene duplication event?

In a sequence of DNA taken from various species of snails, researchers have found that the rates of nonsynonymous substitutions and synonymous substitutions are roughly the same.What can we infer from this pattern?

Which outcome results from the misalignment of highly repeated genes?

Biologists use a chemical derived from a bacterium to help treat sewage waste.This is an example of

Copies of genes in the same or different species that are related as the result of gene duplications are known as

Transitions, which are changes from _______, occur _______ transversions.

Changes to _______ will not affect the phenotype of an organism.

Which statement about about noncoding DNA is true?

In order to estimate the age of the split between the globin gene clusters, scientists did which of the following?

Which statement about synonymous mutations is true?

A number of genes that evolved from duplications of an ancestral gene now code for odor receptors in Drosophila.These odor receptor genes thus comprise a gene

Molecular evolutionists are able to study evolution directly using research models such as viruses, bacteria, and unicellular eukaryotes because substitution rates are related to _______ rather than to _______.

Biased gene conversion is a mechanism of _______ wherein copy number _______.

Refer to the table and sequence. If C were substituted for the nucleotide in position 4 (highlighted) of the sequence, this would be characterized as a _______ nucleotide substitution.

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

Transitions, which are changes from _, occur _ transversions.

Molecular evolutionists are able to study evolution directly using research models such as viruses, bacteria, and unicellular eukaryotes because substitution rates are related to _ rather than to _.

Biased gene conversion is a mechanism of _ wherein copy number _.