Question 1

Which statement about the umbilical cord is true?

Accepted Answer

A)  It contains blood vessels from the embryo. 
B)  It contains blood vessels from the mother. 
C)  It is derived from the amnion. 
D)  It fuses embryonic blood vessels to maternal blood vessels. 
E)  It allows maternal blood to circulate through the embryo. 
A)  It contains blood vessels from the embryo. 
B)  It contains blood vessels from the mother. 
C)  It is derived from the amnion. 
D)  It fuses embryonic blood vessels to maternal blood vessels. 
E)  It allows maternal blood to circulate through the embryo.

Question 2

Which feature characterizes mosaic development?

Accepted Answer

A)  Cell fate is restricted earlier than in regulative development. 
B)  It is typical of vertebrates. 
C)  Cells can compensate for loss of other cells during cleavage. 
D)  It makes preimplantation genetic diagnosis possible without harming the embryo. 
E)  Cells can compensate for loss of other cells during formation of the blastula. 
A)  Cell fate is restricted earlier than in regulative development. 
B)  It is typical of vertebrates. 
C)  Cells can compensate for loss of other cells during cleavage. 
D)  It makes preimplantation genetic diagnosis possible without harming the embryo. 
E)  Cells can compensate for loss of other cells during formation of the blastula.

Question 3

Which feature characterizes the notochord?

Accepted Answer

A)  It develops from ectoderm. 
B)  It is a cartilaginous support in the developing embryo. 
C)  Eventually, it becomes the vertebral column. 
D)  Its cells have organizing capacity. 
E)  It is a type of neural tissue present in early vertebrate embryos. 
A)  It develops from ectoderm. 
B)  It is a cartilaginous support in the developing embryo. 
C)  Eventually, it becomes the vertebral column. 
D)  Its cells have organizing capacity. 
E)  It is a type of neural tissue present in early vertebrate embryos.

Question 4

Refer to the figure.   Which embryo is representative of gastrulation in an amphibian, and which is representative of gastrulation in a reptile? Using the letter labels, identify which structures in the two embryos are homologous.

Accepted Answer

Embryo 1 is representative of

Question 5

The type of development in which each blastomere donates a specific set of items to the final adult animal is called _______ development.

Accepted Answer

The answer of The type of development in which each...

Question 6

Which statement about rotational cleavage is true?

Accepted Answer

A)  The first cleavage plane is rotated at an angle of 45 degrees from the animal-vegetal axis. 
B)  Mitotic spindles are at oblique angles to the animal-vegetal axis for later divisions. 
C)  Two different planes of cleavage occur in the second cell division. 
D)  It is found in monotremes, egg-laying mammals. 
E)  It is a type of incomplete cleavage. 
A)  The first cleavage plane is rotated at an angle of 45 degrees from the animal-vegetal axis. 
B)  Mitotic spindles are at oblique angles to the animal-vegetal axis for later divisions. 
C)  Two different planes of cleavage occur in the second cell division. 
D)  It is found in monotremes, egg-laying mammals. 
E)  It is a type of incomplete cleavage.

Question 7

Which statement about animal development is true?

Accepted Answer

A)  Differentiation of cells into different cell types involves signaling molecules. 
B)  In frog embryos, β-catenin is necessary but not sufficient for the formation of the primary embryonic organizer. 
C)  Blastomeres are early embryonic cells that form during gastrulation. 
D)  The mouth of the sea urchin forms from the blastopore. 
E)  Cells migrate during the blastula stage. 
A)  Differentiation of cells into different cell types involves signaling molecules. 
B)  In frog embryos, β-catenin is necessary but not sufficient for the formation of the primary embryonic organizer. 
C)  Blastomeres are early embryonic cells that form during gastrulation. 
D)  The mouth of the sea urchin forms from the blastopore. 
E)  Cells migrate during the blastula stage.

Question 8

A researcher working with the embryo of the sea snail Ilyanassa allows the embryo to go through two cleavages and then removes one of the four cells.The embryo continues to develop into a swimming larva, but the larva is missing a number of structures, such as the intestine, heart, retractor muscles, and eyes.From this, the researcher is most likely to conclude that

Accepted Answer

A)  the cell that was removed from this sea snail embryo could develop into an intact larva. 
B)  the early embryo of this sea snail is similar to a human embryo in an early stage of development in not being able to regulate after loss of a cell. 
C)  there are informational molecules in the early embryo of this sea snail that restrict the fate of early blastomeres. 
D)  the sea snail embryo will form conjoined twins if it is divided in half at the four-cell stage. 
E)  each cell of the early sea snail embryo is autonomous and able to form a complete larva. 
A)  the cell that was removed from this sea snail embryo could develop into an intact larva. 
B)  the early embryo of this sea snail is similar to a human embryo in an early stage of development in not being able to regulate after loss of a cell. 
C)  there are informational molecules in the early embryo of this sea snail that restrict the fate of early blastomeres. 
D)  the sea snail embryo will form conjoined twins if it is divided in half at the four-cell stage. 
E)  each cell of the early sea snail embryo is autonomous and able to form a complete larva.

Question 9

In the developing chick, the _______ and _______ perform functions equivalent to those of the _______ and _______, respectively, in the developing frog.

Accepted Answer

A)  hypoblast; epiblast; blastopore; dorsal lip of the blastopore 
B)  primitive groove; Hensen's node; blastopore; dorsal lip of the blastopore 
C)  blastodisc; yolk mass; blastopore; dorsal lip of the blastopore 
D)  primitive groove; Hensen's node; dorsal lip of the blastopore; blastodisc 
E)  primitive groove; Hensen's node; blastodisc; dorsal lip of the blastopore 
A)  hypoblast; epiblast; blastopore; dorsal lip of the blastopore 
B)  primitive groove; Hensen's node; blastopore; dorsal lip of the blastopore 
C)  blastodisc; yolk mass; blastopore; dorsal lip of the blastopore 
D)  primitive groove; Hensen's node; dorsal lip of the blastopore; blastodisc 
E)  primitive groove; Hensen's node; blastodisc; dorsal lip of the blastopore

Question 10

An ectopic (tubal) pregnancy in a human occurs when the blastocyst

Accepted Answer

A)  fails to hatch from the zona pellucida. 
B)  hatches too early from the zona pellucida. 
C)  hatches too late from the zona pellucida. 
D)  implants close to the cervix. 
E)  lacks a trophoblast. 
A)  fails to hatch from the zona pellucida. 
B)  hatches too early from the zona pellucida. 
C)  hatches too late from the zona pellucida. 
D)  implants close to the cervix. 
E)  lacks a trophoblast.

Question 11

In humans, gestation lasts for approximately 9 months, which is a _______ period of time than the gestation period of horses.

Accepted Answer

The answer of In humans, gestation lasts for approximately 9...

Question 12

Which feature characterizes cleavage in birds?

Accepted Answer

A)  Cleavage furrows completely divide the egg. 
B)  The embryo forms as a blastodisc on top of the yolk mass. 
C)  Cleavage furrows penetrate the large yolk mass. 
D)  No blastocoel forms. 
E)  It is similar to the early cleavage stages of the fruit fly. 
A)  Cleavage furrows completely divide the egg. 
B)  The embryo forms as a blastodisc on top of the yolk mass. 
C)  Cleavage furrows penetrate the large yolk mass. 
D)  No blastocoel forms. 
E)  It is similar to the early cleavage stages of the fruit fly.

Question 13

In mammals, the cells of the _______ secrete fluid to form the blastocoel.

Accepted Answer

The answer of In mammals, the cells of the _______...

Question 14

Frogs display _______ cleavage, whereas Drosophila display _______ cleavage.

Accepted Answer

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

Question 15

A scientist is running an experiment on anterior organizer cells as they move forward in the blastocoel of a frog embryo.She reactivates growth factors that the anterior organizer cells had suppressed.The most likely result of this experiment is that head structures (will/will not) _______ form in the embryo.

Accepted Answer

The answer of A scientist is running an experiment on...

Question 16

Are conjoined twins identical or non-identical twins, and how do they arise? Does this indicate that humans display mosaic or regulative development?

Accepted Answer

Conjoined twins are identical twins form

Question 17

Many signaling molecules found in the frog organizer have also been found in the chick embryo's

Accepted Answer

A)  primitive neural tube. 
B)  primitive groove. 
C)  Hensen's node. 
D)  endoderm. 
E)  hypoblast. 
A)  primitive neural tube. 
B)  primitive groove. 
C)  Hensen's node. 
D)  endoderm. 
E)  hypoblast.

Question 18

Of the following, which is usually contributed by the sperm at fertilization?

Accepted Answer

A)  mRNAs 
B)  Nutrients 
C)  A diploid nucleus 
D)  A centriole 
E)  Transcription factors 
A)  mRNAs 
B)  Nutrients 
C)  A diploid nucleus 
D)  A centriole 
E)  Transcription factors

Question 19

A researcher experimenting with amphibian embryos is able to prevent the expression of the transcription factor Goosecoid in early organizer cells.The most likely result of this intervention is that

Accepted Answer

A)  anterior growth factors will be suppressed. 
B)  growth factors will be activated that are necessary for head formation. 
C)  the head will form but the trunk and tail will not form. 
D)  certain growth factors will be suppressed and the head will form. 
E)  growth factors preventing head formation will remain active. 
A)  anterior growth factors will be suppressed. 
B)  growth factors will be activated that are necessary for head formation. 
C)  the head will form but the trunk and tail will not form. 
D)  certain growth factors will be suppressed and the head will form. 
E)  growth factors preventing head formation will remain active.

Question 20

A researcher removes the cells containing the germ cell plasm from the vegetal region of a frog blastula.On a second frog blastula, the researcher removes cells from an area that will become the epidermal layer of the skin.What results do you predict from these experiments and why?

Accepted Answer

The first embryo will not develop germ c

Exam 43: Animal Development

Which statement about the umbilical cord is true?

Which feature characterizes mosaic development?

Which feature characterizes the notochord?

Refer to the figure. Which embryo is representative of gastrulation in an amphibian, and which is representative of gastrulation in a reptile? Using the letter labels, identify which structures in the two embryos are homologous.

The type of development in which each blastomere donates a specific set of items to the final adult animal is called _______ development.

Which statement about rotational cleavage is true?

Which statement about animal development is true?

In the developing chick, the _______ and _______ perform functions equivalent to those of the _______ and _______, respectively, in the developing frog.

An ectopic (tubal) pregnancy in a human occurs when the blastocyst

In humans, gestation lasts for approximately 9 months, which is a _______ period of time than the gestation period of horses.

Which feature characterizes cleavage in birds?

In mammals, the cells of the _______ secrete fluid to form the blastocoel.

Frogs display _______ cleavage, whereas Drosophila display _______ cleavage.

Are conjoined twins identical or non-identical twins, and how do they arise? Does this indicate that humans display mosaic or regulative development?

Many signaling molecules found in the frog organizer have also been found in the chick embryo's

Of the following, which is usually contributed by the sperm at fertilization?

A researcher experimenting with amphibian embryos is able to prevent the expression of the transcription factor Goosecoid in early organizer cells.The most likely result of this intervention is that

A researcher removes the cells containing the germ cell plasm from the vegetal region of a frog blastula.On a second frog blastula, the researcher removes cells from an area that will become the epidermal layer of the skin.What results do you predict from these experiments and why?

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In the developing chick, the ___ and _ perform functions equivalent to those of the _ and ___, respectively, in the developing frog.

Frogs display _ cleavage, whereas Drosophila display _ cleavage.