theedaddy77

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May 9, 2008
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what reaction and structure prevents the egg from getting hit up multiple times>? thanks again guys!
 

bruin432

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Jan 26, 2008
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the zona pellucida has receptors for the sperm. The sperm has a structure on its head, which when it is matured, contains enzymes which can breakdown the corona radiata of the oocyte, the reaction in which these enzymes are released is called the acrosome reaction. Once one sperm fertilizes, a series of reactions occur but, mostly there is an increase in Ca++ concentration which hardens the zona pellucida and prevents any other sperm from entering to avoid polyspermia, which in most cases can be fatal (i think thats what its called) hope this helps.
 
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theedaddy77

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May 9, 2008
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ur a bruin so am i!!! so i thought it was the zona pellicude, but on achiever it says none of the above......

Which of the following membrane structures serves as fast block to multiple fertilizations at an animal egg cell 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 pellucida D. Fertilization membrane E. None of the aboveanswer is e. do u have any idea why/.
 

phunki

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Oct 4, 2007
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i think the key word in the question is FAST BLOCK. from what i remember, there is no fast block to polyspermy in animals besides the sea urchin, which has the membrane depolarization.
 

userah

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Aug 9, 2007
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doesn't achiever give out explanations?. it didn't mention anything?