achiever bio question

[pistolpete007]

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Which of the following membrane structures serves as fast block to multiple fertilizations at an animal egg cell?

A.Jelly coat B.Corona radiata C.Zona pellucidaD.Fertilization membrane E.None of the above


cant it be C and D? bc the "stiffed" zona blocks polyspermy in mammals but fertilization membrane blocks in sea urchins and amphibians?

 

[mddang]

Which of the following membrane structures serves as fast block to multiple fertilizations at an animal egg cell?

A.Jelly coatB.Corona radiataC.Zona pellucidaD.Fertilization membraneE.None of the above


cant it be C and D? bc the "stiffed" zona blocks polyspermy in mammals but fertilization membrane blocks in sea urchins and amphibians?

The fast block is the immediate depolarization of the membrane of the egg as a result of the fusion of the first sperm.


After that, there are the cortical reactions which produces the fertilization membrane. This membrane acts to mechanically block and push the other sperm away, sort of like a force field.

Fast block = electric
Slow block = mechanical

 

[TarheelKid24]

Yes, and I would like to say that it would be to your advantage to know this material quite well for the DAT...

 

[pistolpete007]

ok so is the formation of fertilized membrand and stiffined zona formed by the the release of enzymes from the cortical granules to the perivitalle space is what causes the STIFFINED ZONA...this is now how the fertilization membrane is formed tho....is this correct
what is cortical reaction? is it the same thing as i described above because what i described is what happens to a mammel egg.....fertilzation membrane is formed in sea urchins and amphibians
also the formation of ferilzation membrand and the process of stiffined zona is SLOW BLOCK
but the depolarization of the egg is the fast block

 

[Simiam]

ok so is the formation of fertilized membrand and stiffined zona formed by the the release of enzymes from the cortical granules to the perivitalle space is what causes the STIFFINED ZONA...this is now how the fertilization membrane is formed tho....is this correct
what is cortical reaction? is it the same thing as i described above because what i described is what happens to a mammel egg.....fertilzation membrane is formed in sea urchins and amphibians
also the formation of ferilzation membrand and the process of stiffined zona is SLOW BLOCK
but the depolarization of the egg is the fast block

The overall picture:

Sperm loosely attaches to the Zone
Sperm Firmly grasps to the Zona and the Zona allows entry.
The membrane depolarizes the ion gradient which does not allow further sperm entry.
Once the egg and sperm pronuclei fertilize the corticol reaction undergoes a process which causes the zona to become firm and hardened.



That's the way I understand it

 

[pistolpete007]

you are correct

but im asking when the zona b/o hardened is this the same thing as cortisol rxn?...i know cortisol rxn is when a fertilzation membrane forms on amphibians and sea urchinsh....it doesnt form in mammals tho

also are both of these known as slow block?

 

[americanpierg]

AHHHH SO MANY RANDOM QUESTIONS!!! 3 wrong is a 21...how the hell do people get above 21 without being lucky?!

 

[mddang]

you are correct

but im asking when the zona b/o hardened is this the same thing as cortisol rxn?...i know cortisol rxn is when a fertilzation membrane forms on amphibians and sea urchinsh....it doesnt form in mammals tho

also are both of these known as slow block?

yes, it is the same thing