Cleavage Flashcards

1
Q

is a rapid series of mitotic divisions that occur just after fertilization

A

cleavage

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2
Q

During the process of cleavage ,the cell cycle consists of only 2 phases

A

s-phase dna synthesis
m-phase

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3
Q

The cell in cleavage does not go through a ______

A

g1, g2 phases

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4
Q

In the mammals’ ova the first cleavage stage takes ______ which is the lowest
eggs in the yolk.

A

24 hours

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5
Q

In the embryo of birds completes the stages of cleavage

A

before the female lays the egg

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5
Q

In the amphibians 1st cleavage done within

A

3 hours

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6
Q

cleavage in sea urchin embryo

A

radial cleavage

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7
Q

cleavage in mammals

A

rotational cleavage

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8
Q

do not grow in size between successive cell divisions

A

blastomeres

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9
Q

have a small amount of yolk that is equally
distributed in the cytoplasm (most mammal eggs have this)

A

isolecithal eggs

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10
Q

have a moderate amount of yolk, and the
yolk is present mainly in the vegetal hemisphere (amphibians have this)

A

mesolecithal eggs

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11
Q

have a large amount of yolk that fills the
cytoplasm, except for a small area near the animal pole (fish, reptiles, and
birds)

A

telolecithal eggs

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12
Q

have a lot of yolk that is concentrated within the center of
the cell (insects and arthropods).

A

centrolecithal eggs

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13
Q

occurs in isolecithal eggs (mammals, sea urchins). The
entire egg is cleaved during each division.

A

holoblastic cleavage

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14
Q

occurs when eggs have a lot of yolk. The egg does not
divide completely at each division.

A

meroblastic cleavage

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15
Q

is limited to a small disc of cytoplasm at the animal
pole. All of the yolk filled cytoplasm fails to cleave (characteristic of
telolecithal eggs such as birds)

A

discoidal cleavage

16
Q

is limited to a thin surface area of cytoplasm that
covers the entire egg. The inside of the egg that is filled with yolk fails to
cleave (centrolecithal eggs such as insects).

A

superficial cleavage

17
Q

two types of meroblastic cleavage

A

discoidal cleavage
superficial cleavage

18
Q

1st qnd 2nd cleavage

A

meridional

19
Q

The 3rd cleavage is

A

equatorial

20
Q

at the 16 to 32 cell stage the embryo is called a ______ because it looks like a mulberry. Witch will transfer to blastula stage.

A

morula

21
Q

will form at the end of cleavage stage

A

blastula

22
Q

Its has a cavity called the _______ between the animal and vegetal pole

A

blastocoel

23
Q

The outer surface of the amphibian blastula has cells connected by specialized

A

cell junctions

24
Q

create a seal that isolates the outside of an embryo from the
inner layer and polarize the apical and basal surfaces.

A

tight junctions

25
Q

attach the blastomeres together on the outside.

A

desmosomes

26
Q

connect all surface blastomeres.

A

gap junctions

27
Q

The blastula are distributed into 3 areas

A

animal pole, vegetal pole, and in the middle of blastula

28
Q

will develop to the ectoderm witch will give the neural
tube and the skin (epidermis).

A

animal pole

29
Q

(the lower part of the blastula) will form the endoderm
witch will develop and give the elementary canal,lungs

A

vegetal pole

30
Q

will give the mesoderm that will develop and
give the dermis, heart, muscles, bones, kidney.

A

middle of blastula