Deck 47: Animal Development

Question 1

Fertilization of an egg without activation is most like

A)placing the key in the ignition of a car but not starting the engine.
B)resting during halftime of a basketball game.
C)preparing a pie from scratch and baking it in the oven.
D)walking to the cafeteria and eating lunch.
E)dropping a rock off a cliff and watching it land in the valley below.

Answer 1

A

Question 2

The proposal that a human sperm contained a miniature human being is consistent with the now-discredited theory of development known as

A)epigenesis.
B)preformation.
C)cell differentiation.
D)morphogenesis.
E)cell theory.

Answer 2

B

Question 3

In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the

A)acrosomal reaction would be blocked.
B)fusion of sperm and egg nuclei would be blocked.
C)fast block to polyspermy would not occur.
D)fertilization envelope would not be formed.
E)zygote would not contain maternal and paternal chromosomes.

Answer 3

D

Question 4

From earliest to latest, the overall sequence of early development proceeds as follows:

A)first cell division → synthesis of embryo's DNA begins → acrosomal reaction → cortical reaction
B)cortical reaction → synthesis of embryo's DNA begins → acrosomal reaction → first cell division
C)cortical reaction → acrosomal reaction → first cell division → synthesis of embryo's DNA begins
D)first cell division → synthesis of embryo's DNA begins → acrosomal reaction → cortical reaction
E)acrosomal reaction → cortical reaction → synthesis of embryo's DNA begins → first cell division

Question 5

The cortical reaction functions directly in the

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 6

Fertilization normally

A)reinstates diploidy.
B)follows gastrulation.
C)is required for parthenogenesis.
D)merges two dipoloid cells into one haploid cell.
E)precedes ovulation.

Question 7

Compared to sea urchin eggs, those of mammals

A)complete the fertilization process more rapidly.
B)have not already completed meiosis at the time of ovulation.
C)have a more distinct animal pole.
D)have a more distinct vegetal pole.
E)have no requirement for the cortical reaction.

Question 8

Assume that successful reproduction in a rare salamander species, wherein all individuals are females, relies on those females having access to sperm from males of another species but that the resulting embryos show no signs of a genetic contribution from the sperm. In this case, the sperm appear to be used only for

A)morphogenesis.
B)epigenesis.
C)egg activation.
D)cell differentiation.
E)the creation of a diploid cell.

Question 9

From earliest to latest, the overall sequence of early development proceeds as follows:

A)gastrulation → organogenesis → cleavage
B)ovulation → gastrulation → fertilization
C)cleavage → gastrulation → organogenesis
D)gastrulation → blastulation → neurulation
E)preformation → morphogenesis → neurulation

Question 10

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

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

Question 11

Contact of a sperm with signal molecules in the coat of an egg causes the sperm to undergo

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

Question 12

In mammalian eggs, the receptors for sperm are found in the

A)fertilization membrane.
B)zona pellucida.
C)cytosol of the egg.
D)nucleus of the egg.
E)mitochondria of the egg.

Question 13

In mammals, the nuclei resulting from the union of the sperm and the egg are first truly diploid at the end of the

A)acrosomal reaction.
B)completion of spermatogenesis.
C)initial cleavage.
D)activation of the egg.
E)completion of gastrulation.

Question 14

The "slow block" to polyspermy is due to

A)a transient voltage change across the membrane.
B)the consumption of yolk protein.
C)the jelly coat blocking sperm penetration.
D)formation of the fertilization envelope.
E)inactivation of the sperm acrosome.

Question 15

A puppy is born with a malformed right leg. A veterinarian studies the animal and determines that all of the correct types of cells are present, but that the leg simply took on the wrong shape. This is most likely a problem of

A)morphogenesis.
B)cell differentiation.
C)histogenesis.
D)preformation.
E)fertilization.

Question 16

The vitelline layer of the sea urchin egg

A)is outside of the fertilization membrane.
B)releases calcium, which initiates the cortical reaction.
C)has receptor molecules that are specific for binding acrosomal proteins.
D)is first visible only when organogenesis is nearly completed.
E)is a mesh of proteins crossing through the cytosol of the egg.

Question 17

Molecular genetic evidence that certain genes shared by both humans and fruit flies initiate eye development in both species suggest a common

A)complete genome.
B)use of ATP in energy-transfer reactions.
C)genetic toolkit for development.
D)homunculi.
E)duration of pregnancy.

Question 18

You buy a pie that contains a swirled mixture of chocolate and vanilla filling. When you cut the pie up, 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

A)nuclei in a zygote.
B)nuclei in an early embryo.
C)nuclei in an egg.
D)cytoplasmic determinants in a zygote.
E)cytoplasmic determinants in an early embryo.

Question 19

During fertilization, the acrosomal contents

A)block polyspermy.
B)help propel more sperm toward the egg.
C)digest the protective coat on the surface of the egg.
D)nourish the mitochondria of the sperm.
E)trigger the completion of meiosis by the sperm.

Question 20

As an embryo develops, new cells are produced as the result of

A)differentiation.
B)preformation.
C)cell division.
D)morphogenesis.
E)epigenesis.

Question 21

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

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 22

Meroblastic cleavage occurs in

A)sea urchins, but not humans or birds.
B)humans, but not sea urchins or birds.
C)birds, but not sea urchins or humans.
D)both sea urchins and birds, but not humans.
E)both humans and birds, but not sea urchins.

Question 23

Use the following information to answer the following questions.
In a study of the development of frog embryos, several early gastrulas were stained with vital dyes. The locations of the dyes after gastrulation were noted. The results are shown in the following table.
$\begin{array} { l l } \text { Tissue } & \text { Stain } \\\hline \text { Brain } & \text { red } \\\text { Notochord } & \text { yellow } \\\text { Liver } & \text { green } \\\text { Lens of the eye } & \text { blue } \\\text { Lining of the digestive tract } & \text { purple }\end{array}$
Figure 47.1

-The ectoderm should give rise to tissues containing

A)yellow and purple colors.
B)purple and green colors.
C)green and red colors.
D)red and blue colors.
E)red and yellow colors.

Question 24

The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is

A)endoderm → ectoderm → mesoderm.
B)mesoderm → endoderm → ectoderm.
C)ectoderm → mesoderm → endoderm.
D)ectoderm → endoderm → mesoderm.
E)endoderm → mesoderm → ectoderm.

Question 25

In a frog embryo, gastrulation

A)produces a blastocoel displaced into the animal hemisphere.
B)occurs along the primitive streak in the animal hemisphere.
C)is impossible because of the large amount of yolk in the ovum.
D)proceeds by involution as cells roll over the lip of the blastopore.
E)occurs within the inner cell mass that is embedded in the large amount of yolk.

Question 26

A correct statement is:

A)The mesoderm gives rise to the notochord.
B)The endoderm gives rise to the hair follicles.
C)The ectoderm gives rise to the liver.
D)The mesoderm gives rise to the lungs.
E)The ectoderm gives rise to the liver.

Question 27

The vegetal pole of the zygote differs from the animal pole in that

A)the vegetal pole has a higher concentration of yolk.
B)the blastomeres originate only in the vegetal pole.
C)the posterior end of the embryo forms at the vegetal pole.
D)the vegetal pole cells undergo mitosis but not cytokinesis.
E)the polar bodies bud from this region.

Question 28

An open space within the gastrula is the

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

Question 29

The sequence of developmental milestones proceeds as follows:

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 30

The yolk of the frog egg

A)prevents gastrulation.
B)is concentrated at the animal pole.
C)is homogeneously arranged in the egg.
D)impedes the formation of a primitive streak.
E)supports the higher rate of cleavage at the animal pole compared to the vegetal pole.

Question 31

Use the following information to answer the following questions.
In a study of the development of frog embryos, several early gastrulas were stained with vital dyes. The locations of the dyes after gastrulation were noted. The results are shown in the following table.
$\begin{array} { l l } \text { Tissue } & \text { Stain } \\\hline \text { Brain } & \text { red } \\\text { Notochord } & \text { yellow } \\\text { Liver } & \text { green } \\\text { Lens of the eye } & \text { blue } \\\text { Lining of the digestive tract } & \text { purple }\end{array}$
Figure 47.1

-The mesoderm was probably stained with a

A)blue color.
B)yellow color.
C)red color.
D)purple color.
E)green color.

Question 32

Cells move to new positions as an embryo establishes its three germ tissue layers during

A)determination.
B)cleavage.
C)fertilization.
D)induction.
E)gastrulation.

Question 33

The small portion of the embryo that will become its dorsal side develops from the

A)morula.
B)primitive streak.
C)archenteron.
D)gray crescent.
E)blastocoel.

Question 34

An embryo with meroblastic cleavage, extra-embryonic membranes, and a primitive streak must be that of

A)an insect.
B)a fish.
C)an amphibian.
D)a bird.
E)a sea urchin.

Question 35

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

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 36

The archenteron of the developing frog eventually develops into the

A)reproductive organs.
B)the blastocoel.
C)heart and lungs.
D)digestive tract.
E)brain and spinal cord.

Question 37

The vertebrate ectoderm is the origin of the

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

Question 38

If gastrulation was blocked by an environmental toxin, then

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 39

In frog embryos, the blastopore becomes the

A)anus.
B)ears.
C)eyes.
D)nose.
E)mouth.

Question 40

The earliest developmental stage among these choices is

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

Question 41

Use the following information to answer the following questions.
In a study of the development of frog embryos, several early gastrulas were stained with vital dyes. The locations of the dyes after gastrulation were noted. The results are shown in the following table.
$\begin{array} { l l } \text { Tissue } & \text { Stain } \\\hline \text { Brain } & \text { red } \\\text { Notochord } & \text { yellow } \\\text { Liver } & \text { green } \\\text { Lens of the eye } & \text { blue } \\\text { Lining of the digestive tract } & \text { purple }\end{array}$
Figure 47.1

-The endoderm was probably stained with

A)red and yellow colors.
B)yellow and green colors.
C)green and purple colors.
D)blue and yellow colors.
E)purple and red colors.

Question 42

At the time of implantation, the human embryo is called a

A)blastocyst.
B)gastrula.
C)fetus.
D)somite.
E)zygote.

Question 43

Changes in the shape of a cell usually involve a reorganization of the

A)nucleus.
B)cytoskeleton.
C)extracellular matrix.
D)transport proteins.
E)nucleolus.

Question 44

The migratory neural crest cells

A)form most of the central nervous system.
B)serve as precursor cells for the notochord.
C)form the spinal cord in the frog.
D)form neural and non-neural structures in the periphery.
E)form the lining of the lungs and of the digestive tract.

Question 45

A primitive streak forms during the early embryonic development of

A)birds, but not frogs or humans.
B)frogs, but not birds or humans.
C)humans, but not birds or frogs.
D)birds and frogs, but not humans.
E)humans and birds, but not frogs.

Question 46

Although it contributes no cells to the embryo, this structure guides the formation of the primitive streak:

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

Question 47

Uterine implantation due to enzymatic digestion of the endometrium is initiated by

A)the inner cell mass.
B)the endoderm.
C)the chorion.
D)the mesoderm.
E)the trophoblast.

Question 48

If an amphibian zygote is manipulated so that the first cleavage plane fails to divide the gray crescent, then

A)the daughter cell with the entire gray crescent will die.
B)both daughter cells will develop normally because amphibians are totipotent at this stage.
C)only the daughter cell with the gray crescent will develop normally.
D)both daughter cells will develop abnormally.
E)both daughter cells will die immediately.

Question 49

The primitive streak in a bird is the functional equivalent of

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 50

In placental mammals, the yolk sac

A)transfers nutrients from the yolk to the embryo.
B)differentiates into the placenta.
C)becomes a fluid-filled sac that surrounds and protects the embryo.
D)produces blood cells that then migrate into the embryo.
E)stores waste products from the embryo until the placenta develops.

Question 51

In all vertebrate animals, development requires

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

Question 52

During gastrulation in frog embryos, fibronectin provides

A)an extracellular anchorage for migrating cells.
B)regulates actin-myosin interactions in the cytosol of migrating cells.
C)reduces the entry of calcium ions into migrating cells.
D)regulates mRNA movement out of the nucleus of a moving cell.
E)the pigment that accumulates in the primitive streak.

Question 53

Animal development compares to plant development in that

A)plant cells, but not animal cells, migrate during morphogenesis.
B)animal cells, but not plant cells, migrate during morphogenesis.
C)plant cells and animal cells migrate extensively during morphogenesis.
D)neither plant cells nor animal cells migrate during morphogenesis.
E)plant cells, but not animal cells, migrate undergo convergent extension.

Question 54

The least amount of yolk would be found in the egg of a

A)bird.
B)fish.
C)frog.
D)eutherian (placental)mammal.
E)reptile.

Question 55

The term applied to a morphogenetic process whereby cells extend themselves, making the mass of the cells narrower and longer, is

A)convergent extension.
B)induction.
C)elongational streaming.
D)bi-axial elongation.
E)blastomere formation.

Question 56

Changes in both cell shape and cell position occur extensively during

A)gastrulation, but not organogenesis or cleavage.
B)organogenesis, but not gastrulation or cleavage.
C)cleavage, but not gastrulation or organogenesis.
D)gastrulation and organogenesis but not cleavage.
E)gastrulation, organogenesis, and cleavage.

Question 57

Gases are exchanged in a mammalian embryo in the

A)amnion.
B)hypoblast.
C)chorion.
D)trophoblast.
E)yolk sac.

Question 58

Thalidomide, now banned for use as a sedative in pregnancy, was used in the early 1960s by many women in their first trimester of pregnancy. Some of these women gave birth to children with arm and leg deformities, suggesting that the drug most likely influenced

A)early cleavage divisions.
B)determination of the polarity of the zygote.
C)differentiation of bone tissue.
D)morphogenesis.
E)organogenesis.

Question 59

Extraembryonic membranes develop in

A)mammals, but not birds or lizards.
B)birds, but not mammals or lizards.
C)lizards, but not mammals or birds.
D)mammals and birds, but not lizards.
E)mammals, birds, and lizards.

Question 60

Cadherins and other cell-adhesion molecules that guide cell migration are

A)steroid hormones.
B)glycoproteins.
C)fatty acids.
D)prostacyclins.
E)ribonucleic acids.

Question 61

In a frog embryo, the blastocoel is

A)completely obliterated by yolk.
B)lined with endoderm during gastrulation.
C)located in the animal hemisphere.
D)the cavity that becomes the coelom.
E)the cavity that later forms the archenteron.

Question 62

In an amphibian embryo, a band of cells called the neural crest

A)rolls up and forms the neural tube.
B)develops into the main sections of the brain.
C)produces cells that migrate to form teeth, skull bones, and other structures in the embryo.
D)has been shown by experiments to be the organizer region of the developing embryo.
E)induces the formation of the notochord.

Question 63

In frogs, formation of the eye lens is induced by chemical signals from

A)cells that will become the neural plate.
B)cells that are forming the inner ear.
C)an outgrowth of the developing brain.
D)both A and B
E)both A and C

Question 64

The archenteron develops into the

A)mesoderm.
B)blastocoel.
C)endoderm.
D)placenta.
E)lumen of the digestive tract.

Question 65

The arrangement of organs and tissues in their characteristic places in three-dimensional space defines

A)pattern formation.
B)induction.
C)differentiation.
D)determination.
E)organogenesis.

Question 66

Fill in the blanks in the figure below, and draw arrows showing the movement of ectoderm, mesoderm, and endoderm.

Question 67

In humans, identical twins are possible because

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 68

Which of the following is common to the development of both birds and mammals?

A)holoblastic cleavage
B)epiblast and hypoblast
C)trophoblast
D)yolk plug
E)gray crescent

Question 69

The nematode Caenorhabditis elegans

A)is composed of a single cell, in which the developmental origin of each protein has been mapped.
B)is composed of about 1,000 cells, in which the developmental origin of each cell has been mapped.
C)has only a single chromosome, which has been fully sequenced.
D)has about 1,000 genes, each of which has been fully sequenced.
E)uniquely, among animals, utilizes programmed cell death during normal development.

Question 70

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

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

Question 71

If the apical ectodermal ridge is surgically removed from an embryo, it will lose

A)positional information for limb-bud pattern formation.
B)guidance signals needed for correct gastrulation.
C)unequal cytokinesis of blastomeres.
D)the developmental substrate for the gonads.
E)the developmental substrate for the kidneys.

Question 72

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

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 73

Hans Spemann and colleagues developed the concept of the primary organizer in amphibian embryos while studying the

A)medial cells between the optic cups.
B)anterior terminus of the notochord.
C)lateral margins of the neural tube.
D)posterior edge of the dorsal ectoderm.
E)dorsal lip of the blastopore.

Question 74

The cortical reaction of sea urchin eggs functions directly in the

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

Question 75

In the early development of an amphibian embryo, Spemann's "organizer" is located in the

A)neural tube.
B)notochord.
C)archenteron roof.
D)dorsal ectoderm.
E)dorsal lip of the blastopore.