Question 1

The segmented characteristic of human embryonic development is evident from the bricklike structures called _______ that form along the notochord.

Accepted Answer

A)  neural tubes 
B)  mesoderm 
C)  ectoderm 
D)  somites 
E)  somatomeres 
A)  neural tubes 
B)  mesoderm 
C)  ectoderm 
D)  somites 
E)  somatomeres

Question 2

Invagination of the sea urchin blastula

Accepted Answer

A)  is preceded by changes in the shape of individual blastomeres. 
B)  involves the filopodia of secondary mesenchyme cells. 
C)  is due to the uneven distribution of various transcriptional regulatory proteins in the egg cytoplasm. 
D)  forms the archenteron. 
E)  All of the above 
A)  is preceded by changes in the shape of individual blastomeres. 
B)  involves the filopodia of secondary mesenchyme cells. 
C)  is due to the uneven distribution of various transcriptional regulatory proteins in the egg cytoplasm. 
D)  forms the archenteron. 
E)  All of the above

Question 3

If a cell is removed from an eight-cell embryo, and a particular portion of the organism fails to form, the development is termed

Accepted Answer

A)  regulative. 
B)  controlled. 
C)  banished. 
D)  irreversible. 
E)  mosaic. 
A)  regulative. 
B)  controlled. 
C)  banished. 
D)  irreversible. 
E)  mosaic.

Question 4

Roughly how many Hox genes are there in mammals?

Accepted Answer

A)  4 
B)  10 
C)  40 
D)  3,100 
E)  An unknown number; they have been studied in amphibians only. 
A)  4 
B)  10 
C)  40 
D)  3,100 
E)  An unknown number; they have been studied in amphibians only.

Question 5

If cells from the presumptive neural ectoderm of a frog gastrula are transplanted onto the surface of a second gastrula where skin would normally develop, the transplanted cells will still develop into tissues of the nervous system. This experiment shows that the transplanted cells are

Accepted Answer

A)  differentiated. 
B)  totipotent. 
C)  discontinuous. 
D)  determined. 
E)  endodermal. 
A)  differentiated. 
B)  totipotent. 
C)  discontinuous. 
D)  determined. 
E)  endodermal.

Question 6

_______ is a birth defect caused by the failure of the closure of the posterior region of the neural tube.

Accepted Answer

The answer of _______ is a birth defect caused by...

Question 7

During cleavage, the cytoplasm of new cells in a developing frog embryo

Accepted Answer

A)  comes from the egg cytoplasm. 
B)  is synthesized by the blastomeres. 
C)  does not contain any yolk. 
D)  is the vegetal pole. 
E)  undergoes mitosis. 
A)  comes from the egg cytoplasm. 
B)  is synthesized by the blastomeres. 
C)  does not contain any yolk. 
D)  is the vegetal pole. 
E)  undergoes mitosis.

Question 8

Which of the following does not occur during cleavage?

Accepted Answer

A)  Rapid DNA synthesis 
B)  Cell growth 
C)  Differential distribution of nutrients and information molecules 
D)  A rapid series of cell divisions 
E)  Formation of the blastula 
A)  Rapid DNA synthesis 
B)  Cell growth 
C)  Differential distribution of nutrients and information molecules 
D)  A rapid series of cell divisions 
E)  Formation of the blastula

Question 9

The embryos of complex multicellular animals must establish spatial coordinates if development is to proceed. An important reference coordinate for developing frogs is the

Accepted Answer

A)  location of the vegetal pole. 
B)  location of the animal pole. 
C)  point of sperm penetration. 
D)  location where gastrulation begins. 
E)  direction of the sun. 
A)  location of the vegetal pole. 
B)  location of the animal pole. 
C)  point of sperm penetration. 
D)  location where gastrulation begins. 
E)  direction of the sun.

Question 10

How does cleavage in mammals differ from cleavage in frogs?

Accepted Answer

A)  Slower rate of cell division 
B)  Formation of tight junctions 
C)  Expression of the embryo's genome 
D)  Early separation of cells that will not contribute to the embryo 
E)  All of the above 
A)  Slower rate of cell division 
B)  Formation of tight junctions 
C)  Expression of the embryo's genome 
D)  Early separation of cells that will not contribute to the embryo 
E)  All of the above

Question 11

How is the development of the extraembryonic mem­branes different in birds and placental mammals and how is it similar? What accounts for the difference?

Accepted Answer

Both the birds and mammals develop extra

Question 12

Once development has proceeded to the point that three germ layers are in place within the embryo, the next phase of development, called _______, can begin.

Accepted Answer

A)  organogenesis 
B)  gastrulation 
C)  hypoblasty 
D)  epiblasty 
E)  transcription 
A)  organogenesis 
B)  gastrulation 
C)  hypoblasty 
D)  epiblasty 
E)  transcription

Question 13

The period of human gestation is also called _______.

Accepted Answer

The answer of The period of human gestation is also...

Question 14

Which statement about trophoblast cells is true?

Accepted Answer

A)  They are capable of producing monozygotic twins. 
B)  They are derived from the hypoblast of the blastocyst. 
C)  They are endodermal cells. 
D)  They secrete proteolytic enzymes. 
E)  They prevent the zona pellucida from attaching to the oviduct. 
A)  They are capable of producing monozygotic twins. 
B)  They are derived from the hypoblast of the blastocyst. 
C)  They are endodermal cells. 
D)  They secrete proteolytic enzymes. 
E)  They prevent the zona pellucida from attaching to the oviduct.

Question 15

Which of the following statements about neurulation is false?

Accepted Answer

A)  Neural crest cells give rise to peripheral nerves. 
B)  Body segmentation develops during neurulation. 
C)  Hox genes control differentiation along the anterior-posterior body axis. 
D)  Neural crest cells are migratory. 
E)  Neural crest cells break loose from the neural tube adjacent to the line of closure and remain there to contribute to a number of structures. 
A)  Neural crest cells give rise to peripheral nerves. 
B)  Body segmentation develops during neurulation. 
C)  Hox genes control differentiation along the anterior-posterior body axis. 
D)  Neural crest cells are migratory. 
E)  Neural crest cells break loose from the neural tube adjacent to the line of closure and remain there to contribute to a number of structures.

Question 16

The third trimester of human prenatal development is characterized by

Accepted Answer

A)  extremely rapid growth. 
B)  the formation of major organs. 
C)  the greatest sensitivity to damage from drugs and radiation. 
D)  gastrulation. 
E)  the formation of the placenta. 
A)  extremely rapid growth. 
B)  the formation of major organs. 
C)  the greatest sensitivity to damage from drugs and radiation. 
D)  gastrulation. 
E)  the formation of the placenta.

Question 17

The _______ is an important structure for waste storage in birds and some mammals, but not in humans.

Accepted Answer

A)  allantois 
B)  yolk sac 
C)  placenta 
D)  umbilical cord 
E)  amnion 
A)  allantois 
B)  yolk sac 
C)  placenta 
D)  umbilical cord 
E)  amnion

Question 18

During its development, the human embryo is contained within a fluid-filled chamber enclosed by the extraembryonic membrane called the

Accepted Answer

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

Question 19

The primitive groove of bird and mammalian embryos is analogous to the _______ of amphibians and sea urchins.

Accepted Answer

The answer of The primitive groove of bird and mammalian...

Question 20

In mammals, the sac that secretes fluid to form the blastocoel is called the _______.

Accepted Answer

The answer of In mammals, the sac that secretes fluid...

Exam 44: Animal Development

The segmented characteristic of human embryonic development is evident from the bricklike structures called _______ that form along the notochord.

Invagination of the sea urchin blastula

If a cell is removed from an eight-cell embryo, and a particular portion of the organism fails to form, the development is termed

Roughly how many Hox genes are there in mammals?

If cells from the presumptive neural ectoderm of a frog gastrula are transplanted onto the surface of a second gastrula where skin would normally develop, the transplanted cells will still develop into tissues of the nervous system. This experiment shows that the transplanted cells are

_______ is a birth defect caused by the failure of the closure of the posterior region of the neural tube.

During cleavage, the cytoplasm of new cells in a developing frog embryo

Which of the following does not occur during cleavage?

The embryos of complex multicellular animals must establish spatial coordinates if development is to proceed. An important reference coordinate for developing frogs is the

How does cleavage in mammals differ from cleavage in frogs?

How is the development of the extraembryonic mem­branes different in birds and placental mammals and how is it similar? What accounts for the difference?

Once development has proceeded to the point that three germ layers are in place within the embryo, the next phase of development, called _______, can begin.

The period of human gestation is also called _______.

Which statement about trophoblast cells is true?

Which of the following statements about neurulation is false?

The third trimester of human prenatal development is characterized by

The _______ is an important structure for waste storage in birds and some mammals, but not in humans.

During its development, the human embryo is contained within a fluid-filled chamber enclosed by the extraembryonic membrane called the

The primitive groove of bird and mammalian embryos is analogous to the _______ of amphibians and sea urchins.

In mammals, the sac that secretes fluid to form the blastocoel is called the _______.

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How is the development of the extraembryonic membranes different in birds and placental mammals and how is it similar? What accounts for the difference?