Animal 2 Flashcards
the coming together of a male and female gamete to produce a zygote
fertilization
the conversion of a zygote into multicultural embryo
cleavage
forming the structures of the animal body after cleavage
morphogenises
sea urchin reproduction explained
has external fertilization (male and females will release egg in sea water. The sperm has to find egg in sea water. Easier to study in sea water opposed to inside animal’s body
where is the nucleus located in a sea urchin sperm?
in the head of the sperm
membrane bound vessicle at head of sperm that contains hydrolytic enzymes. These break down other chromosomes, trying to break through jelly coat of the egg
acrosome
_____ and egg plasma membrane have sperm binding receptors embedded in them
- vitaline layer
why are the sperm binding proteins so important?
any sperm that wants to fertilize the eggs NEEDS to bind to this
what does the jelly coat do for a sea urchin egg?
protects egg that is free floating in water
also attracts same species sperm by releasing chemicals
how do sea urchin sperm find sea urchin eggs in the open water?
they swim to higher concentrations of specific chemicals that a sea urchin egg’s jelly coat will release
why is a sea urchin egg so much bigger than a sea urchin sperm?
the egg has everything it needs inside itself but the set of chromosomes from the sperm
what is the acrosome reaction and what initiates this?
the release of the acrosome enzymes that digest the jelly coat so the sperm can bind to the membrane proteins
sperm arriving initiate this
how does the sperm attach to the binding proteins?
after acrosome enzymes are relased and jelly coat is gone, acrosome filaments extend into the rod of the sperm, binding the sperm to the protein and initiatinf the fusion of the sperm and egg
when can the sperm move into the egg?
once their membranes are fused
event when multiple sperm fertilize egg
polysperm