Question 1

Which statement about noncoding DNA is false?

Accepted Answer

A)  Noncoding DNA makes up most of the genome in bacteria and yeast. 
B)  Differences in genome size among closely related species are often due to how much noncoding DNA they have. 
C)  Some noncoding DNA may have a function. 
D)  Species vary in the rate at which they lose noncoding DNA. 
E)  Noncoding DNA includes "orphaned" long terminal repeats (LTRs). 
A)  Noncoding DNA makes up most of the genome in bacteria and yeast. 
B)  Differences in genome size among closely related species are often due to how much noncoding DNA they have. 
C)  Some noncoding DNA may have a function. 
D)  Species vary in the rate at which they lose noncoding DNA. 
E)  Noncoding DNA includes "orphaned" long terminal repeats (LTRs).

Question 2

Which scenario would tend to make obtaining correct sequence alignments difficult?

Accepted Answer

A)  Comparing closely related species 
B)  Examining slowly-evolving sequences 
C)  Working with a segment of DNA in which deletions frequently evolve 
D)  Knowing which types of substitutions are most likely to evolve 
E)  Having sequences of a gene from several species at different degrees of evolutionary relatedness from one another 
A)  Comparing closely related species 
B)  Examining slowly-evolving sequences 
C)  Working with a segment of DNA in which deletions frequently evolve 
D)  Knowing which types of substitutions are most likely to evolve 
E)  Having sequences of a gene from several species at different degrees of evolutionary relatedness from one another

Question 3

Which statement provides the strongest evidence that most noncoding DNA is slightly deleterious?

Accepted Answer

A)  Species with larger population sizes have more noncoding DNA. 
B)  Species with smaller population sizes have more noncoding DNA. 
C)  Species with smaller genomes lose DNA more slowly than those with larger genomes. 
D)  Species with larger genomes lose DNA more slowly than those with smaller genomes. 
E)  There is an inverse relationship between the total amount of DNA in the genome and the percentage of the DNA that is noncoding. 
A)  Species with larger population sizes have more noncoding DNA. 
B)  Species with smaller population sizes have more noncoding DNA. 
C)  Species with smaller genomes lose DNA more slowly than those with larger genomes. 
D)  Species with larger genomes lose DNA more slowly than those with smaller genomes. 
E)  There is an inverse relationship between the total amount of DNA in the genome and the percentage of the DNA that is noncoding.

Question 4

Refer to the figure.       Which set of genes contains parologs?

Accepted Answer

A)  Chicken En1 and mouse En1 
B)  Mouse En1 and human En2 
C)  Human En2 and mouse En2 
D)  Sea urchin En and Amphioxus En 
E)  Zebrafish En2a and zebrafish En2b 
A)  Chicken En1 and mouse En1 
B)  Mouse En1 and human En2 
C)  Human En2 and mouse En2 
D)  Sea urchin En and Amphioxus En 
E)  Zebrafish En2a and zebrafish En2b

Question 5

In which organism or organisms would you find the enzyme lysozyme serving a defensive role against invading bacteria?

Accepted Answer

A)  Only in foregut fermenters 
B)  Only in the hoatzin 
C)  Only in foregut fermenters and the hoatzin 
D)  Only in mammals and a few closely related organisms 
E)  In nearly all animals 
A)  Only in foregut fermenters 
B)  Only in the hoatzin 
C)  Only in foregut fermenters and the hoatzin 
D)  Only in mammals and a few closely related organisms 
E)  In nearly all animals

Question 6

The sea snake is resistant to poisoning by the puffer fish sodium channel toxin tetrodoxin (TTX).To determine which regions of the sea snake sodium channel confer resistance, a researcher can _______ the sea snake sodium channel genes.

Accepted Answer

A)  map the missense mutations of 
B)  compare the rates of synonymous and nonsynonymous nucleotide substitutions within 
C)  determine the rate of genetic drift within 
D)  quantify the number of gene duplications within 
E)  map the sequence deletions within 
A)  map the missense mutations of 
B)  compare the rates of synonymous and nonsynonymous nucleotide substitutions within 
C)  determine the rate of genetic drift within 
D)  quantify the number of gene duplications within 
E)  map the sequence deletions within

Question 7

A coincident substitution occurs when

Accepted Answer

A)  a single lineage has one nucleotide change from C to A. 
B)  a nucleotide changes from A to G along one lineage and from A to C along the other lineage. 
C)  a nucleotide changes from A to T in two independently evolving lineages. 
D)  a nucleotide changes from A to T and then to C in a single lineage. 
E)  a nucleotide changes from A to C and then back to A in a single lineage. 
A)  a single lineage has one nucleotide change from C to A. 
B)  a nucleotide changes from A to G along one lineage and from A to C along the other lineage. 
C)  a nucleotide changes from A to T in two independently evolving lineages. 
D)  a nucleotide changes from A to T and then to C in a single lineage. 
E)  a nucleotide changes from A to C and then back to A in a single lineage.

Question 8

As the amount of lateral gene transfer in a taxon increases, 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

Question 9

Which statement about ribosomal RNA (rRNA) genes is false?

Accepted Answer

A)  Nearly all multicellular animals have hundreds of copies of them, if not more. 
B)  Within species the rRNA genes are structurally dissimilar. 
C)  They evolve through concerted evolution. 
D)  They do not evolve independently of one another. 
E)  They are subject to biased gene conversion. 
A)  Nearly all multicellular animals have hundreds of copies of them, if not more. 
B)  Within species the rRNA genes are structurally dissimilar. 
C)  They evolve through concerted evolution. 
D)  They do not evolve independently of one another. 
E)  They are subject to biased gene conversion.

Question 10

Puffer fish possess a chemical called _______ that acts as a toxin by blocking _______.

Accepted Answer

A)  tetrodotoxin; sodium channels 
B)  tetrodotoxin; metabolic enzymes 
C)  ligase; sodium channels 
D)  ligase; metabolic enzymes 
E)  engrailed; sodium channels 
A)  tetrodotoxin; sodium channels 
B)  tetrodotoxin; metabolic enzymes 
C)  ligase; sodium channels 
D)  ligase; metabolic enzymes 
E)  engrailed; sodium channels

Question 11

_______ is most likely to lead to an increase in the rate that pseudogenes accumulate in a population.

Accepted Answer

A)  A decreased point mutation rate 
B)  More intense purifying selection 
C)  An increased rate of gene duplication 
D)  A decreased rate of gene duplication 
E)  An increase in the rate of biased gene conversion 
A)  A decreased point mutation rate 
B)  More intense purifying selection 
C)  An increased rate of gene duplication 
D)  A decreased rate of gene duplication 
E)  An increase in the rate of biased gene conversion

Question 12

You are a molecular evolutionist and have found five successive ancestors of today's Arctic lemming (a type of rodent) frozen in the Arctic permafrost.You sequence the genomes of these ancestral lemmings and the modern lemming.For most genes, if you graph the number of actual substitutions on the x axis and the number of observed substitutions on the y axis, the slope of this graph will most likely

Accepted Answer

A)  be more or less constant and approximately 0. 
B)  be more or less constant and approximately 1/2. 
C)  be more or less constant and approximately 1. 
D)  start off around 0 and increase with increasing divergence. 
E)  start off around 1 and decrease with increasing divergence. 
A)  be more or less constant and approximately 0. 
B)  be more or less constant and approximately 1/2. 
C)  be more or less constant and approximately 1. 
D)  start off around 0 and increase with increasing divergence. 
E)  start off around 1 and decrease with increasing divergence.

Question 13

Humans, mice, rats, chickens, and all other bony vertebrates have two groups of a developmental gene.The most likely explanation is that these two groups of genes arose from a gene duplication event in the common ancestor of

Accepted Answer

A)  humans and mice. 
B)  humans and chickens. 
C)  mice and rats. 
D)  mice and chickens. 
E)  all bony vertebrates. 
A)  humans and mice. 
B)  humans and chickens. 
C)  mice and rats. 
D)  mice and chickens. 
E)  all bony vertebrates.

Question 14

Below are short fragments of DNA sequences from two yeast strains (A and B), which have been diverging from each other, as well as a short fragment from their common ancestor (C). Yeast A: TGACTGCAAACATCCTAG
Yeast B: TGCCTGGACACATCGAAG
Yeast C: TGCCTGGAAACCTCCTAG
What type of information would best allow you to detect whether back substitutions occurred at any of the 18 nucleotides of the sequence as strain A evolved from the common ancestor?

Accepted Answer

A)  Additional sequences from strain A from regions near the 18 nucleotides 
B)  Additional sequences from the ancestor from regions near the 18 nucleotides 
C)  Phenotypic data from strain A and the ancestor 
D)  The 18 nucleotides from yeast samples taken at various times between the ancestor and contemporary strain A 
E)  Sequence data from closely related strains 
A)  Additional sequences from strain A from regions near the 18 nucleotides 
B)  Additional sequences from the ancestor from regions near the 18 nucleotides 
C)  Phenotypic data from strain A and the ancestor 
D)  The 18 nucleotides from yeast samples taken at various times between the ancestor and contemporary strain A 
E)  Sequence data from closely related strains

Question 15

Which genes would most likely experience biased gene conversion?

Accepted Answer

A)  rRNA genes 
B)  Globin genes 
C)  Pseudogenes 
D)  Genes for lysozymes 
E)  Genes that are diverging in function 
A)  rRNA genes 
B)  Globin genes 
C)  Pseudogenes 
D)  Genes for lysozymes 
E)  Genes that are diverging in function

Question 16

The table shows the amino acid sequences for an eight-residue section of a small protein for five different species (1-5).   Which species differs from species 1 because of an amino acid insertion?

Accepted Answer

Species 2 shows an a

Question 17

Which statement about lysozymes is false?

Accepted Answer

A)  Lysozymes are only found in foregut fermenters. 
B)  Lysozymes have been subjected to convergent evolution in mammals. 
C)  At several amino acid positions of these enzymes, nonsynonymous substitutions have occurred faster than have synonymous substitutions in the lineage leading to foregut fermenters. 
D)  The changes that have occurred in the lysozymes of foregut fermenters have made the enzymes more resistant to attack by digestive enzymes. 
E)  Lysozymes digest the cell walls of bacteria. 
A)  Lysozymes are only found in foregut fermenters. 
B)  Lysozymes have been subjected to convergent evolution in mammals. 
C)  At several amino acid positions of these enzymes, nonsynonymous substitutions have occurred faster than have synonymous substitutions in the lineage leading to foregut fermenters. 
D)  The changes that have occurred in the lysozymes of foregut fermenters have made the enzymes more resistant to attack by digestive enzymes. 
E)  Lysozymes digest the cell walls of bacteria.

Question 18

Below are shown segments of DNA from three species of flies.Species 1 is the common ancestor of species 2 and species 3, and we have access to its DNA because it was preserved in amber. Species 1: AACTACTGCACGCTCATA
Species 2: AACTAGTGCTCGCTCACA
Species 3: AATTACTGCACGCTCACA
There have been _______ single and _______ parallel changes as species 2 and 3 evolved from species 1.

Accepted Answer

A)  two; zero 
B)  two; one 
C)  three; zero 
D)  three; one 
E)  four; zero 
A)  two; zero 
B)  two; one 
C)  three; zero 
D)  three; one 
E)  four; zero

Question 19

Which statement about gene families is false?

Accepted Answer

A)  Gene families evolve via gene duplication. 
B)  Pseudogenes are quickly removed from gene families by deletion. 
C)  Members of a gene family can include several functional genes. 
D)  Examples of gene families include the engrailed and globin gene families in vertebrates. 
E)  In some gene families, the members do not evolve independently of one another. 
A)  Gene families evolve via gene duplication. 
B)  Pseudogenes are quickly removed from gene families by deletion. 
C)  Members of a gene family can include several functional genes. 
D)  Examples of gene families include the engrailed and globin gene families in vertebrates. 
E)  In some gene families, the members do not evolve independently of one another.

Question 20

Amino acid sequences of a homologous protein found in three species of dragonflies are presented below: Dragonfly 1: Met-Gln-Leu-Ile-Val-Arg-Ser
Dragonfly 2: Met-Gln-Leu-Ile-Val-Ser
Dragonfly 3: Met-Gln-Leu-Val-Arg-Ser
How many gaps are required to properly align these three species? (Note: Align Dragonfly 2 and Dragonfly 3 sequences with the Dragonfly 1 sequence.)

Accepted Answer

A)  Zero 
B)  One 
C)  Two 
D)  Three 
E)  Four 
A)  Zero 
B)  One 
C)  Two 
D)  Three 
E)  Four

Exam 23: Evolution of Genes and Genomes

Which statement about noncoding DNA is false?

Which scenario would tend to make obtaining correct sequence alignments difficult?

Which statement provides the strongest evidence that most noncoding DNA is slightly deleterious?

Refer to the figure. Which set of genes contains parologs?

In which organism or organisms would you find the enzyme lysozyme serving a defensive role against invading bacteria?

The sea snake is resistant to poisoning by the puffer fish sodium channel toxin tetrodoxin (TTX).To determine which regions of the sea snake sodium channel confer resistance, a researcher can _______ the sea snake sodium channel genes.

A coincident substitution occurs when

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

Which statement about ribosomal RNA (rRNA) genes is false?

Puffer fish possess a chemical called _______ that acts as a toxin by blocking _______.

_______ is most likely to lead to an increase in the rate that pseudogenes accumulate in a population.

Humans, mice, rats, chickens, and all other bony vertebrates have two groups of a developmental gene.The most likely explanation is that these two groups of genes arose from a gene duplication event in the common ancestor of

Which genes would most likely experience biased gene conversion?

The table shows the amino acid sequences for an eight-residue section of a small protein for five different species (1-5). Which species differs from species 1 because of an amino acid insertion?

Which statement about lysozymes is false?

Which statement about gene families is false?

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

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Salt and Water Balance and Nitrogen Excretion

Animal Behavior

The Physical Environment and Biogeography of Life

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A Changing Biosphere

Filters

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

Puffer fish possess a chemical called _ that acts as a toxin by blocking _.