...my health teacher said that we are born will all of our eggs but my bio teacher said that we make them through meiosis....
so which is correct?
thanks :)
2007-06-04 14:03:36 · 29 answers · asked by emily.grace 3 in Science & Mathematics ➔ Biology
the health one
2007-06-07 04:58:33 · answer #1 · answered by manish_wolfyfox 5 · 0⤊ 2⤋
Everybody seems to be partly correct ... unfortunately, probably no one will read down this far to get a complete answer!
Anyways, remember that meiosis involves 2 cell divisions. This is important because it means both of your teachers are right!
Before birth, the cells that will become eggs are set aside and start the first division of meiosis. However, they don't complete the process and enter a stage of suspended development. Technically, they are suspended in the prophase I stage of meiosis I. They stay in this inactive state until puberty. So, in a sense your health teacher is right: the cells which will become eggs are already present at birth.
At puberty, ovulation cycles begin and each month or so, one (or sometimes more) of these suspended eggs becomes active and matures. This process involves restarting and then completing the first division of meiosis. This cell is then ovulated. So, in a sense your biology teacher is right: each month the process of meiosis I is completed and an egg is ovulated.
The egg, now in the Fallopian tube rather than the ovary, is ready to be fertilized. If you were paying attention, however, you noticed it has only completed one of the two divisions that occur during meiosis. This is because the ovulated egg only finishes this second step of meiosis after it has united with a sperm.
So, the final division of meiosis, known as meiosis II, actually happens after ovulation and fertilization. Amazing, isn't it?
If you really want to impress your teachers, though, there is new research that really changes this whole picture ...
A few years ago, scientists discovered that mice can actually make new eggs long after they are born. This was a surprise because, as mentioned by one of the other answerers, all mammals are thought to use the same system as I described above: the developing eggs are set aside before birth and mature only one (or a few) at a time when they are needed.
It is controversial, and still not clear, whether humans can continue to make new eggs after birth, but if you want to wow your teachers, you can print out the second and third links below and show them these new findings ;-)
2007-06-05 13:33:01 · answer #2 · answered by Bad Brain Punk 7 · 1⤊ 0⤋
I remember when I learned about this in biology I had a hard time getting my head around it. Here's the embryo making all it's important parts, like a head and some feet via mitosis. And at the same time the little girl embryos are making eggs via meiosis to make some more babies. The embryo makes the eggs through the process of meiosis and by the time THAT baby pops out it has already made all the eggs that it's going to have. Kind of like it's made all the arms it's going to have, but via meiosis not mitosis. My brain didn't like it at all when I was studying it. But both your teachers are correct; they both just told you half of the whole story.
2007-06-04 22:24:05 · answer #3 · answered by Cyndi 3 · 0⤊ 0⤋
Females are born with all the eggs they will have in life. Each month an egg matures through the process of meiosis to prepare the chromosomes in the egg for eventual fertilization.
2007-06-04 21:08:12 · answer #4 · answered by Anonymous · 1⤊ 1⤋
Girls are born with all the eggs they will ever have. i do believe that they are produced through meiosis because they are just cells with have of the dna stuff in them. but don't quote me on the meiosis part
2007-06-04 21:07:53 · answer #5 · answered by ʚϊɞ Krysti ʚϊɞ 4 · 2⤊ 0⤋
Females are born with all their eggs - thousands of them.
However, at the time they were produced (in the womb), they were formed by meiosis. Both teachers are correct.
Eggs do not go through meiosis again during ovulation. They are merely released from the ovary. "Egg" and "oocyte" refer to the same thing.
2007-06-04 21:07:07 · answer #6 · answered by Bad Kitty! 7 · 1⤊ 1⤋
Both. You are born with a preset number of cells that will become eggs (pre -eggs as it were) in your ovaries. Once they have either matured into eggs or been absorbed by the body, you will not ever get more (and you will head into menopause).
2007-06-04 21:12:21 · answer #7 · answered by Diane A 7 · 0⤊ 0⤋
Health teacher is correct. We are born with all the eggs we will ever have.
2007-06-04 21:11:16 · answer #8 · answered by Mary G 6 · 0⤊ 1⤋
You are born right, although your biology teacher's description is far more accurate. You are born with all the eggs in pre-mature state. At this stage, they are not eggs, yet. As you age, they become mature and become eggs.
2007-06-04 21:12:20 · answer #9 · answered by tkquestion 7 · 0⤊ 0⤋
Both are correct. When a female reaches her puberty, one egg will slowly mature and is released once a month, and undergoes meiosis during oogenesis.
2007-06-04 21:10:18 · answer #10 · answered by no_einstein 4 · 1⤊ 0⤋
Hi. The ovaries contain all the eggs that a woman can produce. They mature one (or more) at a time every 28 days or so.
2007-06-04 21:07:12 · answer #11 · answered by Cirric 7 · 1⤊ 0⤋