Deck 51: Animal Development

Question 1

The fast block to polyspermy involves the

A) release of inhibitors of acrosomal enzymes.
B) synthesis of a new sperm-resistant membrane.
C) accumulation of calcium ions in the acrosome.
D) opening of ion channels that change the polarity of the egg membrane.
E) destruction of excess bindin receptors on the sperm.

Answer 1

D

Question 2

Figure 51-1 ​

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Which of the stages or structures in the accompanying figure was formed by the process of gastrulation?

A) 1
B) f
C) g
D) 3
E) 5

Answer 2

E

Question 3

Which of the following consists of a hollow ball of cells?

A) Gastrula
B) Morula
C) Blastula
D) Blastocoel
E) Zygote

Answer 3

C

Question 4

In sea urchins, the plasma membranes of sperm and egg fuse, and a ______ is formed that contracts to draw the sperm into the egg

A) acrosomal net
B) capacitation network
C) polyspermy barrier
D) fertilization cone
E) granulation expansion

Question 5

Following cleavage of the zygote, although the cell number ____, the embryo ______ in size.

A) increases; decreases
B) increases; increases
C) decreases; increases
D) decreases; decreases
E) increases; does not increase

Question 6

In amphibian development, the blastula consists of many small cells in the _____ hemisphere and fewer but larger cells in the ______ hemisphere.

A) animal; vegetal
B) animal; animal
C) vegetal; vegetal
D) vegetal; animal
E) totipotent; telolecithal

Question 7

In most animals, the sperm and egg contribute an equal ____ to the zygote.

A) amount of cytoplasm
B) number of chromosomes
C) number of enzymes
D) number of mitochondria
E) number of ribosomes

Question 8

If the sperm and egg are of the same species, ______, a species-specific protein located on the _______, adheres to receptors located on the egg's ________.

A) acrosomin; acrosome; jelly coat
B) bindin; acrosome; vitelline membrane
C) bindin; acrosome; zona pellucida
D) acrosomin; zona pellucida, jelly coat
E) bindin, head, vitelline membrane

Question 9

Which of the following indicates the correct sequence of mammalian egg coverings, beginning at the outside and moving inward?

A) Plasma membrane, jelly coat, zona pellucida
B) Zona pellucida, vitelline envelope, plasma membrane
C) Vitelline envelope, plasma membrane, jelly coat
D) Granulosa cells, zona pellucida, plasma membrane
E) Zona pellucida, granulosa cells, plasma membrane

Question 10

Which of the following statements about fertilization is TRUE?

A) Fertilization restores the haploid chromosome number.
B) Fertilization stimulates the initiation of development.
C) Fertilization cannot determine the sex of the offspring.
D) Fertilization permits the formation of gametes with new genetic combinations.
E) In fertilization, a sperm fuses with an ovum to produce an embryo.

Question 11

What is the correct sequence of sea urchin egg coverings, beginning at the inside and moving outward?

A) Granulosa cells, zona pellucida, plasma membrane
B) Zona pellucida, vitelline envelope, plasma membrane
C) Jelly coat, vitelline envelope, plasma membrane
D) Plasma membrane, zona pellucida, jelly coat
E) Vitelline envelope, jelly coat, plasma membrane

Question 12

Figure 51-1 ​

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What type of cleavage pattern is represented in the accompanying figure?

A) Holoblastic and radial
B) Holoblastic and spiral
C) Meroblastic and radial
D) Meroblastic and spiral
E) Holoblastic and mosaic

Question 13

Most invertebrates have

A) isolecithal eggs and meroblastic cleavage.
B) telolecithal eggs and meroblastic cleavage.
C) isolecithal eggs and holoblastic cleavage.
D) telolecithal eggs and holoblastic cleavage.
E) isolecithal eggs and radial cleavage.

Question 14

Before a sperm can participate in fertilization, it must undergo ____ in the female reproductive tract.

A) the acrosome reaction
B) the cortical reaction
C) spermatogenesis
D) determination
E) capacitation

Question 15

Cell division of the blastula is restricted to which of the following?

A) Animal pole
B) Vegetal pole
C) Blastomere
D) Blastodisc
E) Blastocoel

Question 16

Animal growth primarily occurs by an increase in the

A) number of tissues and organs.
B) number of cells.
C) types of cells produced.
D) number of cell functions.
E) number of cell shapes.

Question 17

The principle of nuclear equivalence states that

A) developing cells become specialized to carry out specific functions.
B) developing cells follow particular differentiation pathways.
C) there is no loss of genetic information through determination or differentiation.
D) differential gene expression is responsible for variation among cells.
E) nuclear changes can take place during the entire life of an individual.

Question 18

What is the correct sequence through which early development proceeds?

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

Question 19

Figure 51-1 ​

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The structure labeled as 2 in the accompanying figure is the

A) endoderm layer.
B) mesoderm layer.
C) blastopore.
D) blastocoel.
E) archenteron.

Question 20

Which statement about sperm entry is TRUE?

A) The fertilization cone formed by microvilli of the egg membrane contracts and draws the sperm inward.
B) The egg phagocytizes the acrosome of the sperm so it can enter the cell.
C) The cilia on the egg membrane beat and sweep the sperm inside.
D) The sperm releases calcium ions, which make the egg membrane permeable to its entry.
E) The egg secretes bindin protein, which allows sperm penetration.

Question 21

Figure 51-2 Use the figure to answer the corresponding question(s). ​

​
The developmental stage represented in the accompanying figure is a(n)

A) morula.
B) early blastula.
C) late blastula.
D) early gastrula.
E) middle gastrula.

Question 22

Which structure do cells that make up the upper layer (the epiblast) and migrate toward the midline form?

A) Archenteron
B) Primitive streak
C) Chorion
D) Primitive groove
E) Notochord

Question 23

Figure 51-2 Use the figure to answer the corresponding question(s). ​

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Refer to the accompanying figure. Which structure is the blastocoel?

A) 1
B) 2
C) 3
D) 4
E) 5

Question 24

Figure 51-2 Use the figure to answer the corresponding question(s). ​

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The structure labeled as 3 in Figure 51-2 is the

A) archenteron.
B) endoderm.
C) mesoderm.
D) blastocoel.
E) ectoderm.

Question 25

Figure 51-4 ​

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Refer to the accompanying figure. Which structure is from a different germ layer than the rest?

A) 2
B) 3
C) 6
D) 7
E) 8

Question 26

Which organism exhibits radial cleavage?

A) Echinoderms
B) Amphibians
C) Mollusks
D) Annelids
E) Birds

Question 27

Which of the following arises from the mesoderm?

A) Pituitary gland
B) Inner layer of skin
C) Chorion
D) Outer layer of skin
E) Lining of respiratory system

Question 28

Which of the following becomes the ectoderm during gastrulation?

A) Epiblast
B) Hyoplast
C) Ectoblast
D) Notochord
E) Hensen's node

Question 29

Figure 51-4 ​

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Refer to the accompanying figure. The structure labeled as 2 is the

A) neural plate
B) neural fold
C) notochord
D) somite
E) neural crest

Question 30

The first system to develop in the vertebrate embryo is the

A) circulatory system.
B) digestive system.
C) excretory system.
D) reproductive system.
E) nervous system.

Question 31

A primitive groove is the equivalent of a

A) neural crest.
B) branchial groove.
C) blastodisc.
D) blastopore.
E) neural groove.

Question 32

Embryonic mesoderm forms the

A) epidermis.
B) digestive tract lining.
C) pituitary gland.
D) excretory system.
E) nervous system.

Question 33

The term "archenteron" refers to the developing

A) gut.
B) lung.
C) notochord.
D) nerve tube.
E) skin.

Question 34

The gray crescent region of the amphibian zygote is thought to contain

A) growth factors and developmental determinants.
B) hormones and ribosomes.
C) yolk and dark pigment granules.
D) mitochondria and ribosomes.
E) neurotransmitters and hormones.

Question 35

If the ectoderm is destroyed, which organ systems will not form?

A) Musculoskeletal system
B) Digestive system
C) Nervous system
D) Circulatory system
E) Excretory system

Question 36

Figure 51-4 ​

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Refer to the accompanying figure. Which structure gives rise to the spinal cord?

A) 1
B) 2
C) 5
D) 8
E) 9

Question 37

Embryonic mesoderm gives rise to

A) muscle.
B) the lining of the digestive tract.
C) the nervous system.
D) sense organs.
E) lining of the respiratory system.

Question 38

Which statements about the notochord is FALSE?

A) It is lost when it is replaced by the spinal cord.
B) It develops in chordate embryos.
C) It develops from mesodermal tissue.
D) It induces formation of the neural plate.
E) It grows along the longitudinal axis of the organism.

Question 39

Figure 51-4 ​

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Refer to the accompanying figure. Which structure can be transferred to a different location in the embryo and still cause differentiation of surrounding tissues?

A) 1
B) 2
C) 5
D) 6
E) 8

Question 40

Figure 51-2 Use the figure to answer the corresponding question(s). ​

​
The developing embryo in the accompanying figure is representative of development in a(n)

A) bird.
B) annelid.
C) sea star.
D) frog.
E) mammal.

Question 41

Figure 51-3 ​

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Refer to the accompanying figure. The amnion is identified by number

A) 1
B) 2
C) 3
D) 4
E) 5

Question 42

Briefly explain how cell differentiation relates to pattern formation an animal.

Question 43

Which of the following are incorrectly paired?

A) Heroin−premature births and low birth weight
B) Thalidomide−babies born without toes
C) Accutane−associated with malformations of the brain
D) Cocaine−constricts fetal arteries, which leads to retarded development
E) Cigarette smoking−an addiction to nicotine

Question 44

Which statement about early embryonic development in humans is FALSE?

A) The embryo is moved along the oviduct by ciliary action and muscular contraction.
B) The embryo develops through the blastula stage while floating free in the uterus.
C) The embryo enters the uterus about 24 hours after fertilization.
D) Early division of the embryo occurs in the oviduct.
E) Implantation of the embryo occurs about seven days after fertilization.

Question 45

The extraembryonic membrane closest to the embryo is the

A) amnion.
B) archenteron.
C) chorion.
D) blastocyst.
E) neural plate.

Question 46

The percentage of twins being born has increased in the past 20 years because of

A) the increased use of fertility inducing drugs.
B) increases in hospital care.
C) the desire of more couples to have twins.
D) the increased use of thalidomide.
E) the increased incidence of German measles.

Question 47

The function of the chorion is to

A) absorb shock.
B) form blood cells.
C) provide nourishment.
D) permit freedom of movement.
E) permit gas exchange.

Question 48

A human embryo is capable of movement and has gonads that are distinguishable as either testes or ovaries by the end of the

A) second week.
B) fourth week.
C) sixth week.
D) eighth week.
E) first trimester.

Question 49

The embryo becomes implanted in the endometrium of the uterus due to

A) special receptors on the endometrium to which the blastocyst attaches.
B) enzymes secreted by the trophoblast, which erode an area of the endometrium for entry of the embryo.
C) special phagocytic cells in the endometrium, which engulf the embryo.
D) the sticky coat of the zona pellucida, which adheres to the endometrium.
E) the action of hCG secreted by the embryo.

Question 50

Place the following in developmental order beginning with the earliest event.
(1) Limb buds appear
(2) Face begins to look human
(3) Muscles differentiate
(4) Downy hair covers the fetus
(5) Sex can be determined by external inspection

A) 3, 1, 2, 4, 5
B) 1, 3, 4, 2, 5
C) 1, 3, 2, 5, 4
D) 1, 2, 3, 4, 5
E) 1, 3, 5, 2, 4

Question 51

The trophoblast secretes ____, which signals the corpus luteum that pregnancy has begun.

A) estrogen
B) a gray crescent
C) progesterone
D) hCG
E) an enzyme

Question 52

Which structure is the most immediate precursor of the brain?

A) Neural tube
B) Neural groove
C) Neural crest
D) Neural folds
E) Neural plate

Question 53

Monozygotic twins

A) occur when two eggs are ovulated.
B) may be of different sexes.
C) have different sets of genes.
D) are called identical twins.
E) result from the fertilization of two sperm cells.

Question 54

In mammals, the ____ is a temporary center for the formation of blood cells.

A) amnion
B) allantois
C) yolk sac
D) chorion
E) archenteron

Question 55

Briefly explain the relationship between nuclear equivalence and differential gene expression.

Question 56

A teratogen is a drug that

A) increases fertility.
B) prevents fertilization.
C) prevents implantation of the embryo in the endometrium.
D) induces labor.
E) interferes with morphogenesis.

Question 57

The first breath of the neonate is initiated by the

A) passage through the birth canal.
B) removal of amniotic fluid from its mouth.
C) accumulation of carbon dioxide in the blood.
D) detection of light by its visual receptors.
E) increase in oxygen concentration in the lungs.

Question 58

Figure 51-3 ​

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Refer to the accompanying figure. The chorion is identified by number

A) 1
B) 2
C) 3
D) 4
E) 5

Question 59

In humans, the allantois

A) stores embryonic nitrogenous wastes.
B) eliminates nitrogenous wastes from the embryo.
C) contributes to the formation of the blood vessels in the umbilical cord.
D) secretes amniotic fluid.
E) serves as a temporary center for formation of blood cells.

Question 60

Figure 51-3 ​

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Refer to the accompanying figure. The allantois is identified by number

A) 1
B) 2
C) 3
D) 4
E) 5

Question 61

Using one sentence each and in the correct order, describe the four processes involved in fertilization.

Question 62

In the amphibian embryo, the first cleavage bisects the gray crescent.

Question 63

Programmed cell death is called apoptosis.

Question 64

As part of the fertilization process, the egg completes meiosis I.

Question 65

An embryo having a blastodisc exhibits holoblastic cleavage.

Question 66

Identify two changes that occur at or shortly after birth that allow the neonate to live independently.

Question 67

Gastrulation is the process by which an embryo becomes three-layered.

Question 68

List the fate of each of the three germ layers.

Question 69

In echinoderms, gastrulation takes place through a primitive groove.

Question 70

When a human embryo is implanted in the uterus, the embryo is in the morula stage.

Question 71

The chorion is the extraembryonic membrane closest to the embryo proper.

Question 72

The blastopore is the opening to the blastocoel.

Question 73

During capacitation, sperm become mature.

Question 74

In birds and reptiles, the allantois stores nitrogenous wastes.

Question 75

Isolecithal eggs exhibit holoblastic cleavage.

Question 76

The fertilization envelope forms when the plasma membranes of sperm and egg fuse.

Question 77

The blastula can be described as an embryo consisting of a hollow sphere of cells.

Question 78

Outside the zona pellucida is a layer of granulosa cells.

Question 79

The eggs of birds and reptiles are telolecithal.

Question 80

The notochord induces the neural plate.