Cleavage Flashcards
is a rapid series of mitotic divisions that occur just after fertilization
cleavage
During the process of cleavage ,the cell cycle consists of only 2 phases
s-phase dna synthesis
m-phase
The cell in cleavage does not go through a ______
g1, g2 phases
In the mammals’ ova the first cleavage stage takes ______ which is the lowest
eggs in the yolk.
24 hours
In the embryo of birds completes the stages of cleavage
before the female lays the egg
In the amphibians 1st cleavage done within
3 hours
cleavage in sea urchin embryo
radial cleavage
cleavage in mammals
rotational cleavage
do not grow in size between successive cell divisions
blastomeres
have a small amount of yolk that is equally
distributed in the cytoplasm (most mammal eggs have this)
isolecithal eggs
have a moderate amount of yolk, and the
yolk is present mainly in the vegetal hemisphere (amphibians have this)
mesolecithal eggs
have a large amount of yolk that fills the
cytoplasm, except for a small area near the animal pole (fish, reptiles, and
birds)
telolecithal eggs
have a lot of yolk that is concentrated within the center of
the cell (insects and arthropods).
centrolecithal eggs
occurs in isolecithal eggs (mammals, sea urchins). The
entire egg is cleaved during each division.
holoblastic cleavage
occurs when eggs have a lot of yolk. The egg does not
divide completely at each division.
meroblastic cleavage