Question 1

One of the earliest stages of organogenesis involves the initiation of nervous system development through the process of _______.

Accepted Answer

The answer of One of the earliest stages of organogenesis...

Question 2

In amphibian eggs, cells migrate to the interior of the embryo through the blastopore. In mammalian embryos with small amounts of yolk, this involution occurs at the

Accepted Answer

A)  archenteron. 
B)  primitive groove. 
C)  notochord. 
D)  blastopore. 
E)  gray crescent. 
A)  archenteron. 
B)  primitive groove. 
C)  notochord. 
D)  blastopore. 
E)  gray crescent.

Question 3

After gastrulation, the mesodermal cells contribute to the developing

Accepted Answer

A)  brain and nervous system. 
B)  skeletal system and muscles. 
C)  inner lining of the gut and respiratory tract. 
D)  sweat glands. 
E)  liver and pancreas. 
A)  brain and nervous system. 
B)  skeletal system and muscles. 
C)  inner lining of the gut and respiratory tract. 
D)  sweat glands. 
E)  liver and pancreas.

Question 4

The time from conception to birth, or the period of pregnancy, is also called _______.

Accepted Answer

The answer of The time from conception to birth, or...

Question 5

If you alter cells that are lining the archenteron in a developing vertebrate, such as a frog, you will cause changes in the

Accepted Answer

A)  the lining of the digestive tract, respiratory tract, pancreas, or liver. 
B)  the nervous system, including the eyes and ears. 
C)  structures derived from skin, such as hair, feathers, nails or claws. 
D)  heart, blood vessels, muscle, and bones. 
E)  All of the above 
A)  the lining of the digestive tract, respiratory tract, pancreas, or liver. 
B)  the nervous system, including the eyes and ears. 
C)  structures derived from skin, such as hair, feathers, nails or claws. 
D)  heart, blood vessels, muscle, and bones. 
E)  All of the above

Question 6

In the chick, four extraembryonic membranes form. The membrane that forms a sac to store metabolic wastes is called the

Accepted Answer

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

Question 7

Which of the following is part of the embryonic contribution to placenta formation?

Accepted Answer

A)  Amnion 
B)  Chorion 
C)  Ectoderm 
D)  Allantois 
E)  Zona pellucida 
A)  Amnion 
B)  Chorion 
C)  Ectoderm 
D)  Allantois 
E)  Zona pellucida

Question 8

Which of the following statements about the rearrangement of egg cytoplasm in frogs is false?

Accepted Answer

A)  The haploid nucleus of the egg is located in the animal hemisphere. 
B)  The sperm must always enter into the animal hemisphere. 
C)  The vegetal hemisphere is heavily pigmented. 
D)  The site of sperm entry will become the ventral region. 
E)  The gray crescent will become the dorsal region. 
A)  The haploid nucleus of the egg is located in the animal hemisphere. 
B)  The sperm must always enter into the animal hemisphere. 
C)  The vegetal hemisphere is heavily pigmented. 
D)  The site of sperm entry will become the ventral region. 
E)  The gray crescent will become the dorsal region.

Question 9

In human development, an embryo is most sensitive to chemicals, radiation or pathogens at first trimester, because this is the time that

Accepted Answer

A)  organ systems are growing in size. 
B)  cells are rapidly dividing and tissues are differentiating. 
C)  the enlarged yolk pushes the gastrula into a disk shape. 
D)  the allontoic stalk is disconnected from the placenta. 
E)  All of the above 
A)  organ systems are growing in size. 
B)  cells are rapidly dividing and tissues are differentiating. 
C)  the enlarged yolk pushes the gastrula into a disk shape. 
D)  the allontoic stalk is disconnected from the placenta. 
E)  All of the above

Question 10

Gastrulation is the stage of development

Accepted Answer

A)  when neural tube formation begins. 
B)  that makes possible the inductive interactions that trigger differentiation and organ formation. 
C)  that follows the formation of the three germ layers. 
D)  that precedes cleavage. 
E)  that is marked by a dramatic increase in the rate of mitosis. 
A)  when neural tube formation begins. 
B)  that makes possible the inductive interactions that trigger differentiation and organ formation. 
C)  that follows the formation of the three germ layers. 
D)  that precedes cleavage. 
E)  that is marked by a dramatic increase in the rate of mitosis.

Question 11

Folic acid deficiency during human pregnancy has been shown to lead to _______ in the developing fetus.

Accepted Answer

A)  endodermal defects 
B)  neural tube defects 
C)  cleavage defects 
D)  arrested blastopore development 
E)  mesodermal defects 
A)  endodermal defects 
B)  neural tube defects 
C)  cleavage defects 
D)  arrested blastopore development 
E)  mesodermal defects

Question 12

Chordamesoderm converts some ectoderm into neural ectoderm by

Accepted Answer

A)  increasing the flow of nutrients into those cells. 
B)  hyperexpression of three homeobox genes. 
C)  sequestering folic acid in those cells. 
D)  the first expression of inhibitory hormones in the developing embryo. 
E)  expressing signaling molecules called Noggin and Chordin. 
A)  increasing the flow of nutrients into those cells. 
B)  hyperexpression of three homeobox genes. 
C)  sequestering folic acid in those cells. 
D)  the first expression of inhibitory hormones in the developing embryo. 
E)  expressing signaling molecules called Noggin and Chordin.

Question 13

Which of the following is the distinction between a fetus and an embryo?

Accepted Answer

A)  The term "fetus" applies only to birds. 
B)  The fetus is a mammalian embryo carried longer than 200 days. 
C)  A fetus is the legal term applied to human embryos only. 
D)  By definition, a human fetus becomes an embryo in the second trimester. 
E)  An embryo becomes a fetus at birth. 
A)  The term "fetus" applies only to birds. 
B)  The fetus is a mammalian embryo carried longer than 200 days. 
C)  A fetus is the legal term applied to human embryos only. 
D)  By definition, a human fetus becomes an embryo in the second trimester. 
E)  An embryo becomes a fetus at birth.

Question 14

Which of the following statements about the experiments shown below is true?

Accepted Answer

A)  From these experiments one can conclude that cytoplasmic factors that were equally distributed in the zygote are necessary for normal development. 
B)  These experiments test the hypothesis that cytoplasmic factors necessary for normal development are segregated in the zygote. 
C)  Experiment 1 resulted in one normal embryo and one clump of undifferentiated cells. 
D)  Experiment 2 resulted in two clumps of undifferentiated cells. 
E)  All of the above 
A)  From these experiments one can conclude that cytoplasmic factors that were equally distributed in the zygote are necessary for normal development. 
B)  These experiments test the hypothesis that cytoplasmic factors necessary for normal development are segregated in the zygote. 
C)  Experiment 1 resulted in one normal embryo and one clump of undifferentiated cells. 
D)  Experiment 2 resulted in two clumps of undifferentiated cells. 
E)  All of the above

Question 15

Neural tube defects during development

Accepted Answer

A)  can lead to spina bifida. 
B)  include failure of the tube's folds to fuse in the posterior end. 
C)  are linked to deficiency of folic acid in the diets of pregnant women. 
D)  have declined significantly in the United States in the last 100 years. 
E)  All of the above 
A)  can lead to spina bifida. 
B)  include failure of the tube's folds to fuse in the posterior end. 
C)  are linked to deficiency of folic acid in the diets of pregnant women. 
D)  have declined significantly in the United States in the last 100 years. 
E)  All of the above

Question 16

Which of the following is not a function of the placenta?

Accepted Answer

A)  Waste removal 
B)  Exchange of respiratory gases 
C)  Transfer of nutrients 
D)  Control of the pace of development 
E)  All of the above are functions of the placenta. 
A)  Waste removal 
B)  Exchange of respiratory gases 
C)  Transfer of nutrients 
D)  Control of the pace of development 
E)  All of the above are functions of the placenta.

Question 17

The primary embryonic organizer is most likely initiated by

Accepted Answer

A)  the yolk. 
B)  Tcf-3 protein. 
C)  $\beta$-catenin. 
D)  cAMP. 
E)  None of the above 
A)  the yolk. 
B)  Tcf-3 protein. 
C)  $\beta$-catenin. 
D)  cAMP. 
E)  None of the above

Question 18

The structure in birds and mammals that is most analogous to the dorsal lip of the frog blastopore is

Accepted Answer

A)  the primitive streak. 
B)  the archenteron. 
C)  the yolk plug. 
D)  Hensen's node. 
E)  the notochord. 
A)  the primitive streak. 
B)  the archenteron. 
C)  the yolk plug. 
D)  Hensen's node. 
E)  the notochord.

Question 19

Discoidal cleavage

Accepted Answer

A)  results in embryos that have little yolk. 
B)  results when there is little interference with cleavage furrow formation. 
C)  completely divides the egg. 
D)  occurs in sea urchins. 
E)  occurs in animals with large yolks, such as reptiles and birds 
A)  results in embryos that have little yolk. 
B)  results when there is little interference with cleavage furrow formation. 
C)  completely divides the egg. 
D)  occurs in sea urchins. 
E)  occurs in animals with large yolks, such as reptiles and birds

Question 20

The protein that induces cells in the neural tube to develop into motor neurons is named after which video-game character?

Accepted Answer

A)  Donkey Kong 
B)  Sonic hedgehog 
C)  Mario 
D)  Pac Man 
E)  Galaga 
A)  Donkey Kong 
B)  Sonic hedgehog 
C)  Mario 
D)  Pac Man 
E)  Galaga

Exam 44: Animal Development

One of the earliest stages of organogenesis involves the initiation of nervous system development through the process of _______.

In amphibian eggs, cells migrate to the interior of the embryo through the blastopore. In mammalian embryos with small amounts of yolk, this involution occurs at the

After gastrulation, the mesodermal cells contribute to the developing

The time from conception to birth, or the period of pregnancy, is also called _______.

If you alter cells that are lining the archenteron in a developing vertebrate, such as a frog, you will cause changes in the

In the chick, four extraembryonic membranes form. The membrane that forms a sac to store metabolic wastes is called the

Which of the following is part of the embryonic contribution to placenta formation?

Which of the following statements about the rearrangement of egg cytoplasm in frogs is false?

In human development, an embryo is most sensitive to chemicals, radiation or pathogens at first trimester, because this is the time that

Gastrulation is the stage of development

Folic acid deficiency during human pregnancy has been shown to lead to _______ in the developing fetus.

Chordamesoderm converts some ectoderm into neural ectoderm by

Which of the following is the distinction between a fetus and an embryo?

Which of the following statements about the experiments shown below is true?

Neural tube defects during development

Which of the following is not a function of the placenta?

The primary embryonic organizer is most likely initiated by

The structure in birds and mammals that is most analogous to the dorsal lip of the frog blastopore is

Discoidal cleavage

The protein that induces cells in the neural tube to develop into motor neurons is named after which video-game character?

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