Question 1

The conclusion of Spemann's work,in which he tied off a zygote isolating the nucleus on one side and only cytoplasm on the other,helped prove

Accepted Answer

A)  origin of the coelom.
B)  nuclear equivalency.
C)  cytoplasmic specification.
D)  embryonic induction.E) A) and B)
F) None of the above

Question 2

After the fusion of sperm and egg membranes,there is the release of enzyme-rich granules from the egg that ultimately causes the separation of the vitelline envelope and the egg membrane;this is called

Accepted Answer

A)  polyspermy.
B)  pronucleation.
C)  the cortical reaction.
D)  cytoplasmic localization.E) All of the above
F) B) and D)

Question 3

In nearly all metazoa,"germ layers" is a term that describes

Accepted Answer

A)  the germ cells.
B)  foreign cells that enter the embryonic process.
C)  mesoderm,ectoderm and endoderm.
D)  the germ line,in contrast to the somatic or body cells.E) A) and B)
F) A) and C) C

Question 4

Generally,only one sperm fertilizes an egg because

Accepted Answer

A)  there are so few sperm that two are unlikely to arrive at the same time.
B)  sperm compete and only the most fit one is accepted.
C)  many sperm enter but only one set of chromosomes fuses with the egg nucleus;excess sperm are absorbed.
D)  when the first sperm membrane fuses with the egg membrane,a barrier to other sperm forms.E) All of the above
F) A) and B)

Question 5

"Diploblastic" refers to ________ where _________.

Accepted Answer

A)  fish and amphibians,cells divide in two synchronously
B)  sea stars and humans,development can proceed in two directions
C)  birds and reptiles,the egg must be completely nourished within a shell
D)  cnidarians and comb jellies,only two germ layers are formed
E)  only mammals,advanced neural structures are formedF) A) and D)
G) A) and C)

Question 6

The abnormal entrance of more than one sperm into an egg,normally prevented by the fertilization membrane,is called _______________.

Accepted Answer

polyspermy

Question 7

Eggs with abundant yolk that is concentrated at the vegetal pole are called

Accepted Answer

A)  mesolecithal.
B)  holoblastic.
C)  isolecithal.
D)  telolecithal.E) A) and B)
F) All of the above

Question 8

Neighboring cells influence the development of each other,either by direct contact or by production of chemical signals,in

Accepted Answer

A)  neurulation.
B)  induction.
C)  maternal determinants.
D)  homeotic pattern formation.E) B) and C)
F) None of the above

Question 9

The difference between primary and secondary induction is a difference between

Accepted Answer

A)  "hard-wired" commands and chance development.
B)  effects of the dorsal lip organizer and effects of the subsequent cell's induction.
C)  nuclear and cytoplasmic determinants.
D)  homeotic pattern formation and regular structural gene effects.E) C) and D)
F) B) and D)

Question 10

Somites,which form segmental muscles and vertebrae,develop from which germ layer?

Accepted Answer

A)  Ectoderm
B)  Endoderm
C)  Mesoderm
D)  MyodermE) None of the above
F) B) and D)

Question 11

The special blastomere labeled the 4-d cell often gives rise to the

Accepted Answer

A)  endoderm of many protostomes.
B)  endoderm of many deuterostomes.
C)  mesoderm of many protostomes.
D)  mesoderm of many deuterostomes.
E)  ectoderm of many protostomes.F) A) and D)
G) B) and C)

Question 12

Superficial cleavage is found in

Accepted Answer

A)  amphibians.
B)  mammals.
C)  sea stars.
D)  insects.E) B) and D)
F) All of the above

Question 13

The neural tube of vertebrates develops by

Accepted Answer

A)  folding of ectoderm tissue.
B)  migration of mesoderm cells.
C)  fusion of ectoderm and mesoderm.
D)  extension of endoderm into a thin spinal column.E) A) and B)
F) None of the above

Question 14

A true coelom is a fluid-filled cavity completely lined by ___________.

Accepted Answer

The answer of A true coelom is a fluid-filled cavity...

Question 15

In an amniotic egg,the amnion

Accepted Answer

A)  serves as a repository for wastes produced by the developing embryo.
B)  serves as a respiratory surface for the exchange of oxygen and carbon dioxide.
C)  is a fluid-filled sac that protects the embryo from shocks and adhesions.
D)  develops into the chorio-allantoic membrane.E) B) and D)
F) All of the above

Question 16

If yolk is primarily food storage for the developing embryo,why is it so central to understanding cleavage?

Accepted Answer

The yolk within an egg cell is indeed a source of nutrients for the developing embryo, but it also plays a crucial role in the process of cleavage, which is the series of rapid cell divisions that occur after fertilization. Understanding the relationship between yolk and cleavage is important for several reasons:

1. **Yolk Distribution and Cleavage Patterns**: The amount and distribution of yolk in the egg can affect the pattern of cleavage. In eggs with little yolk (isolecithal eggs), such as those of mammals, cleavage is typically holoblastic, meaning that the entire egg divides completely with each cleavage event. In contrast, in eggs with a large amount of yolk (telolecithal eggs), such as those of birds and reptiles, cleavage is meroblastic, meaning that cell division occurs only in the yolk-free cytoplasmic region of the egg. This is because the dense yolk inhibits the cleavage furrow from passing through it.

2. **Rate of Cell Division**: The presence of yolk can slow down the rate of cell division in the areas where it is concentrated. Cells that contain less yolk divide more rapidly than those with more yolk. This leads to an uneven rate of division and can result in different cell sizes, which is important for the future differentiation of cells into various tissues and organs.

3. **Embryonic Axes Formation**: The distribution of yolk within the egg can influence the establishment of the embryonic axes (anterior-posterior, dorsal-ventral, left-right). As cells divide and interact with the yolk and each other, they begin to establish the body plan of the developing organism.

4. **Nutrient Provision**: The yolk not only serves as a nutrient reserve but also influences the timing of gene expression and metabolic activity in the developing embryo. As cells cleave and form the blastula, they will eventually need to access the yolk's resources for further growth and development.

5. **Cell Fate Determination**: The position of cells relative to the yolk can affect their developmental fate. In some species, the yolk contains determinants that influence the developmental pathway of the cells that inherit them during cleavage.

6. **Evolutionary Adaptations**: The adaptations in cleavage patterns in response to yolk distribution reflect the evolutionary pressures on different species. For example, the large yolk of bird eggs supports the development of the embryo on land, without the need for additional water or nutrients from the environment.

In summary, the yolk's role in providing nutrition is closely tied to the mechanics and regulation of cleavage. Its influence on the rate, pattern, and symmetry of cell division, as well as its impact on the subsequent developmental processes, makes it central to our understanding of early embryonic development.

Question 17

Discuss or outline the derivatives of endoderm,mesoderm,and ectoderm.

Accepted Answer

The derivatives of the three primary ger...

Question 18

The concept of ________ suggested that preformed animals in the egg unfolded during development.

Accepted Answer

The answer of The concept of ________ suggested that preformed...

Question 19

The major group of the animal kingdom that includes animals that in their development show spiral cleavage and mosaic development is the __________.

Accepted Answer

The answer of The major group of the animal kingdom...

Question 20

The point of fertilization occurs when

Accepted Answer

A)  sperm are deposited in the vagina.
B)  sperm reach the outer jelly coating of the egg.
C)  sperm tails are shed.
D)  the sperm nucleus and egg nucleus unite to form a zygote.E) A) and C)
F) B) and C)

Exam 8: Principles of Development

The conclusion of Spemann's work,in which he tied off a zygote isolating the nucleus on one side and only cytoplasm on the other,helped prove

Correct Answer
verified

After the fusion of sperm and egg membranes,there is the release of enzyme-rich granules from the egg that ultimately causes the separation of the vitelline envelope and the egg membrane;this is called

Correct Answer
verified

In nearly all metazoa,"germ layers" is a term that describes

Correct Answer
verified
C

Generally,only one sperm fertilizes an egg because

Correct Answer
verified

"Diploblastic" refers to where _.

Correct Answer
verified

The abnormal entrance of more than one sperm into an egg,normally prevented by the fertilization membrane,is called _______________.

Correct Answer
verified
polyspermy

Eggs with abundant yolk that is concentrated at the vegetal pole are called

Correct Answer
verified

Neighboring cells influence the development of each other,either by direct contact or by production of chemical signals,in

Correct Answer
verified

The difference between primary and secondary induction is a difference between

Correct Answer
verified

Somites,which form segmental muscles and vertebrae,develop from which germ layer?

Correct Answer
verified

The special blastomere labeled the 4-d cell often gives rise to the

Correct Answer
verified

Superficial cleavage is found in

Correct Answer
verified

The neural tube of vertebrates develops by

Correct Answer
verified

A true coelom is a fluid-filled cavity completely lined by ___________.

Correct Answer
verified

In an amniotic egg,the amnion

Correct Answer
verified

If yolk is primarily food storage for the developing embryo,why is it so central to understanding cleavage?

Discuss or outline the derivatives of endoderm,mesoderm,and ectoderm.

Correct Answer
Answered by ExamLex AI
The derivatives of the three primary ger...
View Answer

The concept of ________ suggested that preformed animals in the egg unfolded during development.

Correct Answer
verified

The major group of the animal kingdom that includes animals that in their development show spiral cleavage and mosaic development is the __________.

Correct Answer
verified

The point of fertilization occurs when

Correct Answer
verified

Exam 8: Principles of Development

The conclusion of Spemann's work,in which he tied off a zygote isolating the nucleus on one side and only cytoplasm on the other,helped prove

Correct AnswerverifiedShow Answer

After the fusion of sperm and egg membranes,there is the release of enzyme-rich granules from the egg that ultimately causes the separation of the vitelline envelope and the egg membrane;this is called

Correct AnswerverifiedShow Answer

In nearly all metazoa,"germ layers" is a term that describes

Correct AnswerverifiedC

Generally,only one sperm fertilizes an egg because

Correct AnswerverifiedShow Answer

"Diploblastic" refers to ________ where _________.

Correct AnswerverifiedShow Answer

The abnormal entrance of more than one sperm into an egg,normally prevented by the fertilization membrane,is called _______________.

Correct Answerverifiedpolyspermy

Eggs with abundant yolk that is concentrated at the vegetal pole are called

Correct AnswerverifiedShow Answer

Neighboring cells influence the development of each other,either by direct contact or by production of chemical signals,in

Correct AnswerverifiedShow Answer

The difference between primary and secondary induction is a difference between

Correct AnswerverifiedShow Answer

Somites,which form segmental muscles and vertebrae,develop from which germ layer?

Correct AnswerverifiedShow Answer

The special blastomere labeled the 4-d cell often gives rise to the

Correct AnswerverifiedShow Answer

Superficial cleavage is found in

Correct AnswerverifiedShow Answer

The neural tube of vertebrates develops by

Correct AnswerverifiedShow Answer

A true coelom is a fluid-filled cavity completely lined by ___________.

Correct AnswerverifiedShow Answer

In an amniotic egg,the amnion

Correct AnswerverifiedShow Answer

If yolk is primarily food storage for the developing embryo,why is it so central to understanding cleavage?

Discuss or outline the derivatives of endoderm,mesoderm,and ectoderm.

Correct AnswerAnswered by ExamLex AIThe derivatives of the three primary ger...View AnswerShow Answer

The concept of ________ suggested that preformed animals in the egg unfolded during development.

Correct AnswerverifiedShow Answer

The major group of the animal kingdom that includes animals that in their development show spiral cleavage and mosaic development is the __________.

Correct AnswerverifiedShow Answer

The point of fertilization occurs when

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
C

Correct Answer
verified

"Diploblastic" refers to where _.

Correct Answer
verified

Correct Answer
verified
polyspermy

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
The derivatives of the three primary ger...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified