Sea Urchin Question

[ddsnp]

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Hey guys there has been a lot of talk about the sea urchin. I had a bio class where they talked about the fertilization of the sea urchin and i think this statment may proove to be important.

"The binding of sperm to the vitelline envelope triggers the egg plasma membrane to depolarize, preventing other sperm from fusing with the plasma membrane."

BTW the vitellin envelope is a jelly like surface on the egg. These are once again echinoderms.

Hope this helps all of us on the test haha..

 

[mochafreak]

Hmmm, if that would in fact help for that question, you wouldn't really need to know anything about Sea Urchins per se, since that sounds pretty much like what happens in humans...right? In any case, it sounds like we better know the development stuff pretty well.

 

[ddsnp]

Hmmm, if that would in fact help for that question, you wouldn't really need to know anything about Sea Urchins per se, since that sounds pretty much like what happens in humans...right? In any case, it sounds like we better know the development stuff pretty well.

I just think they may ask of details like vitelline envelope but i may be wrong

 

[SpikeyMike83]

that was the question i had i believe. I'm not certain though. I think I ended up saying that the answer was to prevent polyspermy or something like that.

 

[cowsgomoo]

Hmmm, if that would in fact help for that question, you wouldn't really need to know anything about Sea Urchins per se, since that sounds pretty much like what happens in humans...right? In any case, it sounds like we better know the development stuff pretty well.

Yeah but in humans it’s called the zona pellucida. And remember this is a slow response to poly-fertilization (or something like that).

 

[ddsnp]

that was the question i had i believe. I'm not certain though. I think I ended up saying that the answer was to prevent polyspermy or something like that.

i think that was right

 

[mochafreak]

Yeah but in humans it's called the zona pellucida. And remember this is a slow response to poly-fertilization (or something like that).

Yeah, that's what I was referring too...what do you mean by slow response though? The first block to polyspermy is the wave of Ca2+ after sperm penetration and then the second block is the cortical rxn...the hardening of the zona pellucida. Is the Ca2+ wave considered the fast response?

 

[cowsgomoo]

Yeah, that's what I was referring too...what do you mean by slow response though? The first block to polyspermy is the wave of Ca2+ after sperm penetration and then the second block is the cortical rxn...the hardening of the zona pellucida. Is the Ca2+ wave considered the fast response?

Yeah since that is due to the acrosome of sperm.

 

[mahme]

Wow...all this talk about acrosomes, zona pellucida, etc....I remember reading about it in the MCAT books but I don't think it's in the Kaplan 2000 book. Do I need to know that stuff??

 

[cowsgomoo]

Wow...all this talk about acrosomes, zona pellucida, etc....I remember reading about it in the MCAT books but I don't think it's in the Kaplan 2000 book. Do I need to know that stuff??

Yeah its not in kaplan DAT book but it is in Kaplan ap bio book.

 

[dentwannabe]

Yeah its not in kaplan DAT book but it is in Kaplan ap bio book.

first is fast block to polyspermy
depolarization
-short term

second is long term slow block to polyspermy
- enzymes in egg cause outer membrane to harden.

 

[xylashellx]

i think i put that answer on the test wooooooooooooooooooo...didnt really help much for my 18 GC

 

[cowsgomoo]

first is fast block to polyspermy
depolarization
-short term

second is long term slow block to polyspermy
- enzymes in egg cause outer membrane to harden.

Yup. Did I get it wrong?

 

[ddsnp]

Does anyone know how long it takes for topscore to be mailed out? I ordered it last week I think friday.

 

[mahme]

I think you can download it online then get them to mail you the activation key.

 

[cowsgomoo]

Does anyone know how long it takes for topscore to be mailed out? I ordered it last week I think friday.

I got mine in like 3 days but thats because there office is in GA.

 

[Flipper405]

Yeah, that's what I was referring too...what do you mean by slow response though? The first block to polyspermy is the wave of Ca2+ after sperm penetration and then the second block is the cortical rxn...the hardening of the zona pellucida. Is the Ca2+ wave considered the fast response?

Isn't it Na+? We just covered this in class yesterday. My teacher could have been wrong, but I'm not sure.