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destroyer bio 94

Discussion in 'DAT Discussions' started by pistolpete007, Jun 14, 2008.

  1. pistolpete007

    pistolpete007 2+ Year Member

    May 18, 2008
    I dont agree with All being correct answers because for C "the sea urchin can develop a tough protective envelope called the FERTILIZATION MEMBRANE as a block to polyspermy....i dont think this is is true bc according to Schaums pg 155-156 this happens in amphibeans

    in sea urchins you have (pg 154)the cortical granules in the periphery ofthe egg sytoplasm that fuse with the overlying plasma membrane, and a avariety of enzymes are released into the perivitelline space. it ise these enzymes that cause a stiffening of zona pellucida and an associated loss of its ability to bind sperm. The stiffened zona provides a long-term block to polyspermy.

    so there is no fertilization membrane in sea urchins but rather a stiffening of zona that blocks polyspermy.....

    is schaums wrong or destroyer?
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  3. lphiewok

    lphiewok ACFAS Member 7+ Year Member

    Aug 19, 2007
    Fort Polk, LA
    i have no idea which one is right or wrong
    but under my vocab list, i have zone pellucida as a jelly coat surrounding an egg cell. so maybe we can think zone pellucida as a part of the fertilization membrane so maybe both of them are right?

    yeah i hate studying between different studying materials since many of them do not always use either same terms or same descriptions of what's happening
  4. klutzy1987

    klutzy1987 StudyingSucks Letsgo Mets 5+ Year Member

    Jan 28, 2008
    New York
    dude stop reading schaums it seems to have alot of mistakes and unnecessary infoormation judging from yours and previous posts. I would switch to cliffs if i were you. I am 100% sure that destroyer is correct in this question and just take what destroyer says as fact and ignore other books unless you are sure there is a mistake. Sea urchins do develop a double membrane to prevent polyspermy. If you took devlopmental bio in college you will remember that there is a fast block and a slow block to polyspermy.
  5. Orgodox

    Orgodox 7+ Year Member

    Feb 8, 2008
    New York
    I actually just read this again yesterday. You are reading the paragraph wrong. What you quoted is what happens in mammals. KEEP READING... the next sentence says that in sea urchins the changes are more modes than in mammals "in sea urchin, in which a PATENT FERTILIZED MEMBRANE FORMS above the eggs plasma membrane and actually pushes the extraneous sperm away"
    I actually read this and was like huh then had to read it again and realized how it goes. So you see destroyer and schaums are both right!
    Good luck
  6. excusezmoi

    excusezmoi 2+ Year Member

    Apr 13, 2007
    Yeah, schaums and destroyer are both right. I think the slow block is fertilization membrane while the acrosomal reaction *something is the fast block. But I think if you use cliffs' it kinda give you a straight to the point explanation.

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