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Reproduction

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Reproduction

Postby MIA6 » Wed Mar 28, 2007 3:17 am

1. In sexual reproduction, man has primary sex cells in the testes, so my questions is: how many primary sex cells release sperms once? it's not that only one primary sex cell releases sperms once, right? It can be 'many' primary sex cells release sperms at the same time? So how about women? How many primary sex cells release eggs once?
2. Binary fission is an asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size, so for an example, if a paramecium reproduces, itself divides into two other parameciums? so itself dies?

Thanks for help!
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Re: Reproduction

Postby Revenged » Wed Mar 28, 2007 11:51 am

MIA6 wrote:1. In sexual reproduction, man has primary sex cells in the testes, so my questions is: how many primary sex cells release sperms once? it's not that only one primary sex cell releases sperms once, right? It can be 'many' primary sex cells release sperms at the same time? So how about women? How many primary sex cells release eggs once?

Thanks for help!


1) I'm not entirely sure what you are asking but you need to realise the important differents between males and females gamete production...

Male gamete production only starts at puberty and it doesn't stop... Also one spermatogonia produces four speratids (whereas one oogonia produces only one secondary oocytes)...

Female gamete production starts also starts at puberty but the numbers of primordial follicles degenerate until menopause when there is no more primordial follicles left...

Hormonal control ensures that only one secondary oocyte is released once a month and females reach menopause at approx 50 years females...
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Postby Darby » Sat Mar 31, 2007 5:48 pm

Also, spermatogonia don't just produce sperm, they also produce more spermatogonia, so the supply never runs out.

The oogonia are all made sometime around birth, so it is a finite source (although I just read an article that asserts that this isn't true). Still, I was under the impression that the idea that menopause happens when the original oogonia / primordial follicles are gone was no longer believed - that it was more of a straightforward timing issue.

But one thing I'm sure of: when you discuss human reproduction, there is a huge amount of conflicting information out there. Part of the problem is that actual studies of humans are almost impossible to do, and animals vary quite a lot and aren't really comparable to us in this area.
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Postby Balpreet » Sun Apr 22, 2007 2:46 pm

for women it is once every month unless she is pregnant
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Postby Darby » Sun Apr 22, 2007 4:32 pm

One is how many get ovulated, usually, but not how many enter the cycle. Usually, 3-6 primary oocytes begin to develop (one follicle probably wouldn't generate enough hormones), but one retards the progress of the others and becomes the only one to be released.
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