Question 1

The primitive streak in a bird is the functional equivalent of

Accepted Answer

A)  the lip of the blastopore in the frog. 
B)  the archenteron in a frog. 
C)  polar bodies in a sea urchin. 
D)  the notochord in a mammal. 
E)  neural crest cells in a mammal. 
A)  the lip of the blastopore in the frog. 
B)  the archenteron in a frog. 
C)  polar bodies in a sea urchin. 
D)  the notochord in a mammal. 
E)  neural crest cells in a mammal.

Question 2

When you slice up a pie that contains a swirled mixture of chocolate and vanilla filling, you notice that some slices have more chocolate than vanilla and that other slices have more vanilla than chocolate. This uneven distribution of chocolate and vanilla is most like the uneven distribution of

Accepted Answer

A)  nuclei in a zygote. 
B)  nuclei in an early embryo. 
C)  nuclei in an egg prior to fertilization. 
D)  cytoplasmic determinants in a newly formed zygote. 
E)  cytoplasmic determinants in a baby just prior to birth. 
A)  nuclei in a zygote. 
B)  nuclei in an early embryo. 
C)  nuclei in an egg prior to fertilization. 
D)  cytoplasmic determinants in a newly formed zygote. 
E)  cytoplasmic determinants in a baby just prior to birth.

Question 3

In humans, identical twins are possible because

Accepted Answer

A)  of the heterogeneous distribution of cytoplasmic determinants in unfertilized eggs. 
B)  of interactions between extraembryonic cells and the zygote nucleus. 
C)  of convergent extension. 
D)  early blastomeres can form a complete embryo if isolated. 
E)  the gray crescent divides the dorsal-ventral axis into new cells. 
A)  of the heterogeneous distribution of cytoplasmic determinants in unfertilized eggs. 
B)  of interactions between extraembryonic cells and the zygote nucleus. 
C)  of convergent extension. 
D)  early blastomeres can form a complete embryo if isolated. 
E)  the gray crescent divides the dorsal-ventral axis into new cells.

Question 4

Two primary factors in shaping the polarity of the body axes in chick embryos are

Accepted Answer

A)  light and temperature. 
B)  salt gradients and membrane potentials. 
C)  gravity and pH. 
D)  moisture and mucus. 
E)  location of sperm penetration and cortical reaction. 
A)  light and temperature. 
B)  salt gradients and membrane potentials. 
C)  gravity and pH. 
D)  moisture and mucus. 
E)  location of sperm penetration and cortical reaction.

Question 5

A human blastomere is

Accepted Answer

A)  an embryonic cell that is much smaller than the ovum. 
B)  an embryonic structure that includes a fluid-filled cavity. 
C)  that part of the acrosome that opens the egg's membrane. 
D)  a component of the zona pellucida. 
E)  a cell that contains a (degenerating) second polar body. 
A)  an embryonic cell that is much smaller than the ovum. 
B)  an embryonic structure that includes a fluid-filled cavity. 
C)  that part of the acrosome that opens the egg's membrane. 
D)  a component of the zona pellucida. 
E)  a cell that contains a (degenerating) second polar body.

Question 6

As cleavage continues during frog development, the size of the blastomeres

Accepted Answer

A)  increases as the number of the blastomeres decreases. 
B)  increases as the number of the blastomeres increases. 
C)  decreases as the number of the blastomeres increases. 
D)  decreases as the number of the blastomeres decreases. 
E)  increases as the number of the blastomeres stays the same. 
A)  increases as the number of the blastomeres decreases. 
B)  increases as the number of the blastomeres increases. 
C)  decreases as the number of the blastomeres increases. 
D)  decreases as the number of the blastomeres decreases. 
E)  increases as the number of the blastomeres stays the same.

Question 7

A sea urchin zygote undergoes its first cell division

Accepted Answer

A)  5 seconds after fertilization. 
B)  30 minutes after fertilization. 
C)  90 minutes after fertilization. 
D)  4 hours after fertilization. 
E)  24 hours after fertilization. 
A)  5 seconds after fertilization. 
B)  30 minutes after fertilization. 
C)  90 minutes after fertilization. 
D)  4 hours after fertilization. 
E)  24 hours after fertilization.

Question 8

The vertebrate ectoderm is the origin of the

Accepted Answer

A)  nervous system. 
B)  liver. 
C)  pancreas. 
D)  heart. 
E)  kidneys. 
A)  nervous system. 
B)  liver. 
C)  pancreas. 
D)  heart. 
E)  kidneys.

Question 9

Contact of a sea urchin egg with signal molecules on sperm causes the egg to undergo a brief

Accepted Answer

A)  mitosis. 
B)  membrane depolarization. 
C)  apoptosis. 
D)  vitellogenesis. 
E)  acrosomal reaction. 
A)  mitosis. 
B)  membrane depolarization. 
C)  apoptosis. 
D)  vitellogenesis. 
E)  acrosomal reaction.

Question 10

The earliest developmental stage among these choices is

Accepted Answer

A)  germ layers. 
B)  morula. 
C)  blastopore. 
D)  gastrulation. 
E)  invagination. 
A)  germ layers. 
B)  morula. 
C)  blastopore. 
D)  gastrulation. 
E)  invagination.

Question 11

In all vertebrate animals, development requires

Accepted Answer

A)  a large supply of yolk. 
B)  an aqueous environment. 
C)  extraembryonic membranes. 
D)  an amnion. 
E)  a primitive streak. 
A)  a large supply of yolk. 
B)  an aqueous environment. 
C)  extraembryonic membranes. 
D)  an amnion. 
E)  a primitive streak.

Question 12

If gastrulation was blocked by an environmental toxin, then

Accepted Answer

A)  cleavage would not occur in the zygote. 
B)  embryonic germ layers would not form. 
C)  fertilization would be blocked. 
D)  the blastula would not be formed. 
E)  the blastopore would form above the gray crescent in the animal pole. 
A)  cleavage would not occur in the zygote. 
B)  embryonic germ layers would not form. 
C)  fertilization would be blocked. 
D)  the blastula would not be formed. 
E)  the blastopore would form above the gray crescent in the animal pole.

Question 13

Which of the following correctly displays the sequence of developmental milestones?

Accepted Answer

A)  cleavage → blastula → gastrula → morula 
B)  cleavage → gastrula → morula → blastula 
C)  cleavage → morula → blastula → gastrula 
D)  gastrula → morula → blastula → cleavage 
E)  morula → cleavage → gastrula → blastula 
A)  cleavage → blastula → gastrula → morula 
B)  cleavage → gastrula → morula → blastula 
C)  cleavage → morula → blastula → gastrula 
D)  gastrula → morula → blastula → cleavage 
E)  morula → cleavage → gastrula → blastula

Question 14

What structural adaptation in chickens allows them to lay their eggs in arid environments rather than in water?

Accepted Answer

A)  extraembryonic membranes 
B)  yolk 
C)  cleavage 
D)  gastrulation 
E)  development of the brain from ectoderm 
A)  extraembryonic membranes 
B)  yolk 
C)  cleavage 
D)  gastrulation 
E)  development of the brain from ectoderm

Question 15

The cortical reaction functions directly in the

Accepted Answer

A)  formation of a fertilization envelope. 
B)  production of a fast block to polyspermy. 
C)  release of hydrolytic enzymes from the sperm cell. 
D)  generation of a nerve-like impulse by the egg cell. 
E)  fusion of egg and sperm nuclei. 
A)  formation of a fertilization envelope. 
B)  production of a fast block to polyspermy. 
C)  release of hydrolytic enzymes from the sperm cell. 
D)  generation of a nerve-like impulse by the egg cell. 
E)  fusion of egg and sperm nuclei.

Question 16

During the early part of the cleavage stage in frog development, the rapidly developing cells

Accepted Answer

A)  skip the mitosis phase of the cell cycle. 
B)  skip the S phase of the cell cycle. 
C)  skip the G₁ and G₂ phases of the cell cycle. 
D)  rapidly increase the volume and mass of the embryo. 
E)  skip the cytokinesis phase of the cell cycle. 
A)  skip the mitosis phase of the cell cycle. 
B)  skip the S phase of the cell cycle. 
C)  skip the G₁ and G₂ phases of the cell cycle. 
D)  rapidly increase the volume and mass of the embryo. 
E)  skip the cytokinesis phase of the cell cycle.

Question 17

In sea urchins, the "fast block" and the longer lasting "slow block" to polyspermy, respectively, are

Accepted Answer

A)  the acrosomal reaction and the formation of egg white. 
B)  the cortical reaction and the formation of yolk protein. 
C)  the jelly coat of the egg and the vitelline membrane. 
D)  membrane depolarization and the cortical reaction. 
E)  inactivation of the sperm acrosome. 
A)  the acrosomal reaction and the formation of egg white. 
B)  the cortical reaction and the formation of yolk protein. 
C)  the jelly coat of the egg and the vitelline membrane. 
D)  membrane depolarization and the cortical reaction. 
E)  inactivation of the sperm acrosome.

Question 18

Although it contributes no cells to the embryo, the formation of the primitive streak is guided by the structure known as the

Accepted Answer

A)  endoderm. 
B)  mesoderm. 
C)  ectoderm. 
D)  neural crest. 
E)  hypoblast. 
A)  endoderm. 
B)  mesoderm. 
C)  ectoderm. 
D)  neural crest. 
E)  hypoblast.

Question 19

In a newly fertilized egg, the vitelline layer

Accepted Answer

A)  opens the egg's nuclear membrane to allow haploid sperm DNA to enter. 
B)  hardens to form a protective cover. 
C)  secretes hormones that enhance steroidogenesis by the ovary. 
D)  reduces the loss of water from the egg and prevents desiccation. 
E)  provides most of the nutrients used by the zygote. 
A)  opens the egg's nuclear membrane to allow haploid sperm DNA to enter. 
B)  hardens to form a protective cover. 
C)  secretes hormones that enhance steroidogenesis by the ovary. 
D)  reduces the loss of water from the egg and prevents desiccation. 
E)  provides most of the nutrients used by the zygote.

Question 20

In a developing frog embryo, most of the yolk is

Accepted Answer

A)  located near the animal pole. 
B)  located near the vegetal pole. 
C)  found within the cleavage furrow. 
D)  found within the blastocoels. 
E)  distributed equally throughout the embryo. 
A)  located near the animal pole. 
B)  located near the vegetal pole. 
C)  found within the cleavage furrow. 
D)  found within the blastocoels. 
E)  distributed equally throughout the embryo.

Exam 47: Animal Development

The primitive streak in a bird is the functional equivalent of

When you slice up a pie that contains a swirled mixture of chocolate and vanilla filling, you notice that some slices have more chocolate than vanilla and that other slices have more vanilla than chocolate. This uneven distribution of chocolate and vanilla is most like the uneven distribution of

In humans, identical twins are possible because

Two primary factors in shaping the polarity of the body axes in chick embryos are

A human blastomere is

As cleavage continues during frog development, the size of the blastomeres

A sea urchin zygote undergoes its first cell division

The vertebrate ectoderm is the origin of the

Contact of a sea urchin egg with signal molecules on sperm causes the egg to undergo a brief

The earliest developmental stage among these choices is

In all vertebrate animals, development requires

If gastrulation was blocked by an environmental toxin, then

Which of the following correctly displays the sequence of developmental milestones?

What structural adaptation in chickens allows them to lay their eggs in arid environments rather than in water?

The cortical reaction functions directly in the

During the early part of the cleavage stage in frog development, the rapidly developing cells

In sea urchins, the "fast block" and the longer lasting "slow block" to polyspermy, respectively, are

Although it contributes no cells to the embryo, the formation of the primitive streak is guided by the structure known as the

In a newly fertilized egg, the vitelline layer

In a developing frog embryo, most of the yolk is

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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