Question 1

The earliest stage of development is called the _______ stage.

Accepted Answer

A)  fetal 
B)  cleavage 
C)  gastrula 
D)  blastula 
E)  trophoblast 
A)  fetal 
B)  cleavage 
C)  gastrula 
D)  blastula 
E)  trophoblast B

Question 2

Gastrulation in reptiles and birds includes a thickening called Hensen's node, which is similar to the dorsal lip of an amphibian blastopore. Based on this, you would expect to see _______ in this region.

Accepted Answer

A)  neural tube cells 
B)  signaling molecules that organize the developing embryo 
C)  modified mesodermal tissue 
D)  a well-developed archenteron 
E)  None of the above 
A)  neural tube cells 
B)  signaling molecules that organize the developing embryo 
C)  modified mesodermal tissue 
D)  a well-developed archenteron 
E)  None of the above B

Question 3

Of the three germ layers that develop during gastrulation, the _______ layer gives rise to the lining of the digestive tract.

Accepted Answer

endoderm

Question 4

The gray crescent is the region of the egg

Accepted Answer

A)  that is opposite the site of sperm penetration. 
B)  where gastrulation begins. 
C)  that was pigmented before cytoplasmic rearrangement. 
D)  where the dorsal lip of the blastopore develops. 
E)  All of the above 
A)  that is opposite the site of sperm penetration. 
B)  where gastrulation begins. 
C)  that was pigmented before cytoplasmic rearrangement. 
D)  where the dorsal lip of the blastopore develops. 
E)  All of the above

Question 5

The mesoderm gives rise to

Accepted Answer

A)  the lining of the digestive tract, respiratory tract, pancreas, and 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, and 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

All of the following are characteristic of early chick development except

Accepted Answer

A)  rotational cleavage. 
B)  hypoblast. 
C)  epiblast. 
D)  Hensen's node. 
E)  blastocoel. 
A)  rotational cleavage. 
B)  hypoblast. 
C)  epiblast. 
D)  Hensen's node. 
E)  blastocoel.

Question 7

Which of the following statements about animal development is false?

Accepted Answer

A)  Signaling molecules interact to produce different combinations of signals that eventually guide embryonic cells to differentiate along different pathways. 
B)  $\beta$-catenin is necessary but not sufficient for the formation of the primary embryonic organizer. 
C)  Blastomeres are early embryonic cells. 
D)  The mouth of the sea urchin forms where the archenteron makes contact with the ectoderm. 
E)  Cells actively migrate during gastrulation. 
A)  Signaling molecules interact to produce different combinations of signals that eventually guide embryonic cells to differentiate along different pathways. 
B)  $\beta$-catenin is necessary but not sufficient for the formation of the primary embryonic organizer. 
C)  Blastomeres are early embryonic cells. 
D)  The mouth of the sea urchin forms where the archenteron makes contact with the ectoderm. 
E)  Cells actively migrate during gastrulation.

Question 8

The rupturing of two extraembryonic membranes and the loss of the _______ fluid signals the beginning of labor in humans.

Accepted Answer

The answer of The rupturing of two extraembryonic membranes and...

Question 9

In organisms such as the chick, in which the egg has extensive yolk, the egg

Accepted Answer

A)  shows complete cleavage. 
B)  shows incomplete cleavage. 
C)  forms a blastoderm but no blastocoel. 
D)  shows even distribution of the yolk. 
E)  fails to synthesize DNA during cleavage. 
A)  shows complete cleavage. 
B)  shows incomplete cleavage. 
C)  forms a blastoderm but no blastocoel. 
D)  shows even distribution of the yolk. 
E)  fails to synthesize DNA during cleavage.

Question 10

Which of the following is true of human development?

Accepted Answer

A)  Most organs begin to form during the second trimester. 
B)  Gastrulation takes place in the oviducts. 
C)  Genetic diseases can be detected by sampling cells from the chorion. 
D)  Implantation occurs through interactions of the zona pellucida with the uterine lining. 
E)  Exposure to drugs and chemicals is most likely to cause birth defects when it occurs in the third trimester. 
A)  Most organs begin to form during the second trimester. 
B)  Gastrulation takes place in the oviducts. 
C)  Genetic diseases can be detected by sampling cells from the chorion. 
D)  Implantation occurs through interactions of the zona pellucida with the uterine lining. 
E)  Exposure to drugs and chemicals is most likely to cause birth defects when it occurs in the third trimester.

Question 11

Thalidomide is a drug known to disrupt limb development. Why might exposure to thalidomide during the first trimester cause more severe birth defects than a similar level of exposure in the third trimester?

Accepted Answer

Exposure to thalidomide during the first

Question 12

The movement of cells toward the blastopore is called

Accepted Answer

A)  mass cellular migration. 
B)  embryonic cellular integration. 
C)  cellular destiny. 
D)  furrowing. 
E)  epiboly. 
A)  mass cellular migration. 
B)  embryonic cellular integration. 
C)  cellular destiny. 
D)  furrowing. 
E)  epiboly.

Question 13

In early cleavage, sea urchins undergo _______ cleavage, whereas insects undergo _______ cleavage.

Accepted Answer

A)  complete; superficial 
B)  complete; incomplete 
C)  superficial; incomplete 
D)  incomplete; complete 
E)  superficial; complete 
A)  complete; superficial 
B)  complete; incomplete 
C)  superficial; incomplete 
D)  incomplete; complete 
E)  superficial; complete

Question 14

The dorsal lip of the blastopore organizes embryo formation in frogs. The equivalent structure in chickens is

Accepted Answer

A)  the epiblast. 
B)  the hypoblast. 
C)  Hensen's node. 
D)  the bottle cell. 
E)  the gray crescent. 
A)  the epiblast. 
B)  the hypoblast. 
C)  Hensen's node. 
D)  the bottle cell. 
E)  the gray crescent.

Question 15

A fate map can be used to map out the tissues and organs that eventually will develop from specific germ layers. On the fate map, ectoderm will become

Accepted Answer

A)  the lining of the gut. 
B)  the nervous system. 
C)  muscle. 
D)  the heart. 
E)  the lining of the respiratory tract. 
A)  the lining of the gut. 
B)  the nervous system. 
C)  muscle. 
D)  the heart. 
E)  the lining of the respiratory tract.

Question 16

Which of the following statements about events during the neurulation stage of development is false?

Accepted Answer

A)  Neurulation initiates the nervous system. 
B)  The notochord gives structural support to the embryo. 
C)  Bulges at the posterior end of the neural tube become the brain. 
D)  The likelihood of a neural tube defect is lowered if a pregnant woman takes folic acid. 
E)  Both a and b 
A)  Neurulation initiates the nervous system. 
B)  The notochord gives structural support to the embryo. 
C)  Bulges at the posterior end of the neural tube become the brain. 
D)  The likelihood of a neural tube defect is lowered if a pregnant woman takes folic acid. 
E)  Both a and b

Question 17

A recent public health campaign in Australia called for the mandatory inclusion of folic acid in bread. Which of the following would be a likely result of this measure?

Accepted Answer

A)  Since folic acid increases the probability that sperm will initiate an acrosome reaction and thereby fertilize eggs, a long-term population decline in the country would be reversed. 
B)  Since folic acid aids in the fusion of folds of the neural tube, birth defects would be reduced. 
C)  Since folic acid stiffens the zona pellucida, thereby selecting for the strongest sperm, birth defects would be reduced. 
D)  It would accelerate weight gain in chickens, thereby increasing their market availability. 
E)  All of the above 
A)  Since folic acid increases the probability that sperm will initiate an acrosome reaction and thereby fertilize eggs, a long-term population decline in the country would be reversed. 
B)  Since folic acid aids in the fusion of folds of the neural tube, birth defects would be reduced. 
C)  Since folic acid stiffens the zona pellucida, thereby selecting for the strongest sperm, birth defects would be reduced. 
D)  It would accelerate weight gain in chickens, thereby increasing their market availability. 
E)  All of the above

Question 18

Which of the following statements about the mammalian blastocyst is false?

Accepted Answer

A)  The trophoblast gives rise to the embryo proper. 
B)  Maternal genes are expressed during cleavage. 
C)  The blastocyst implants itself in the mother's uterus. 
D)  Early mammalian cleavage is relatively slow. 
E)  The trophoblast contributes to formation of the chorion. 
A)  The trophoblast gives rise to the embryo proper. 
B)  Maternal genes are expressed during cleavage. 
C)  The blastocyst implants itself in the mother's uterus. 
D)  Early mammalian cleavage is relatively slow. 
E)  The trophoblast contributes to formation of the chorion.

Question 19

Which of the following is not a name or term used by developmental biologists?

Accepted Answer

A)  Sonic Hedgehog 
B)  Noggin 
C)  Goosecoid 
D)  Mario 
E)  Siamois 
A)  Sonic Hedgehog 
B)  Noggin 
C)  Goosecoid 
D)  Mario 
E)  Siamois

Question 20

If the blastopore dorsal lip is grafted from one frog embryo onto a second embryo, the second dorsal lip will

Accepted Answer

A)  change the polarity of the adjacent segments. 
B)  block gastrulation. 
C)  change the developmental fate of the surrounding cells. 
D)  change the prospective potency of the surrounding cells. 
E)  cause rapid cell division. 
A)  change the polarity of the adjacent segments. 
B)  block gastrulation. 
C)  change the developmental fate of the surrounding cells. 
D)  change the prospective potency of the surrounding cells. 
E)  cause rapid cell division.

Exam 44: Animal Development

The earliest stage of development is called the _______ stage.

Gastrulation in reptiles and birds includes a thickening called Hensen's node, which is similar to the dorsal lip of an amphibian blastopore. Based on this, you would expect to see _______ in this region.

Of the three germ layers that develop during gastrulation, the _______ layer gives rise to the lining of the digestive tract.

The gray crescent is the region of the egg

The mesoderm gives rise to

All of the following are characteristic of early chick development except

Which of the following statements about animal development is false?

The rupturing of two extraembryonic membranes and the loss of the _______ fluid signals the beginning of labor in humans.

In organisms such as the chick, in which the egg has extensive yolk, the egg

Which of the following is true of human development?

Thalidomide is a drug known to disrupt limb development. Why might exposure to thalidomide during the first trimester cause more severe birth defects than a similar level of exposure in the third trimester?

The movement of cells toward the blastopore is called

In early cleavage, sea urchins undergo _______ cleavage, whereas insects undergo _______ cleavage.

The dorsal lip of the blastopore organizes embryo formation in frogs. The equivalent structure in chickens is

A fate map can be used to map out the tissues and organs that eventually will develop from specific germ layers. On the fate map, ectoderm will become

Which of the following statements about events during the neurulation stage of development is false?

A recent public health campaign in Australia called for the mandatory inclusion of folic acid in bread. Which of the following would be a likely result of this measure?

Which of the following statements about the mammalian blastocyst is false?

Which of the following is not a name or term used by developmental biologists?

If the blastopore dorsal lip is grafted from one frog embryo onto a second embryo, the second dorsal lip will

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In early cleavage, sea urchins undergo _ cleavage, whereas insects undergo _ cleavage.