gametogenesis

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zonia30
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gametogenesis

Post by zonia30 » Sat May 13, 2006 8:43 pm

can anybody please explain this process to me in plain easy to understand words its my exams in june and this is one part i cannot figure out at all!!! :(

Doc44
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Post by Doc44 » Sat May 13, 2006 11:23 pm

Generally speaking, gametogenesis is the production of gametes, sex cells, sperm and egg. In animals it takes place in gonads; testis and ovary. The process involves meiosis, reduction division and mitosis, regular cell division. The resulting gametes have only one half the number of chromosomes as the organism's somatic, body, cells. Humans have 46 chromosomes (diploid, 2N) and their gametes only have 23 chromosomes (haploid 1N).....so when a sperm combines with an egg (fertilization) the resulting zygote has 46. This maintains a constant number of chromosomes in a species from generation to generation.

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Biologically speaking, the only function of an organism is to survive long enough to reproduce......good luck.

zonia30
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Post by zonia30 » Sun May 14, 2006 1:03 pm

cheers doc! so basically the cell replicates first then begins to divide is that right??????

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Post by Doc44 » Sun May 14, 2006 3:49 pm

zonia30 wrote:cheers doc! so basically the cell replicates first then begins to divide is that right??????


That is what happens in mitosis. In gametogenesis there is division by meiosis before the division by mitosis.
In higher animals there are two forms of gametogenesis; spermatogenesis and oogenesis. Here is a pretty good diagram of spermatogenesis. See if this helps.

Spermatogenesis

http://www.umanitoba.ca/faculties/scien ... enesis.jpg

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If still not clear I will splain it.

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gametogenesis

Post by atypical10 » Wed May 17, 2006 11:02 pm

Gametogenesis is basically the production of gametes, gametes are sex cells either sperm (male) or egg (female). During meiosis, after two sucessive dvisions four haploid gametes are produced and chromoso-
-ome numbers are reduced by half.

zonia30
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Post by zonia30 » Fri Jun 02, 2006 5:23 pm

cheers that website helped xxx
so see if im right i only need the basics
a cell 46 chromosomes replicates (mitosis) itself
1st meiotic division occurs producing 2 cells containing 23 chromosomes
2nd meiotic division occurs producing another 2 daughter cells still containing 23 ????????????????????????????????????????
now i get confused
please help i usually ok at understanding things but this is winding me up i cant get it like i said i only need to know basics of both sperm and ooogenesis whatever lol
thanks alot i appreciate it
:roll:

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MrMistery
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Post by MrMistery » Fri Jun 02, 2006 5:44 pm

the cells with 23 chromosomes formed after meiosis I are each composed of 2 sister chromatids, while ones formed after meisis II have only one chromatid each
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

zonia30
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Post by zonia30 » Sat Jun 03, 2006 8:30 pm

thanks for that think its finally sunk in thanks for all the help xx :P

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jnkdna
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Post by jnkdna » Mon Jun 05, 2006 12:07 pm

hey did u have ur exams today? june 5th dat is.
d nyt is darkest just before the dawn

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