2007-01-04 15:25:28 · 5 answers · asked by dundundun 1 in Science & Mathematics ➔ Biology
*but why? how is 11?
2007-01-04 15:32:33 · update #1
think about it this way... If a toad sperm/egg cell were to contain 22 chromosomes, (instead of 11) and it combined with its complementary sex cell which also had 22 chromosome you would get a zygote with 44 chromosomes. The sex cells for this toad would then have cells with 44 chromosomes and would need an organism with 44 chromosomes for reproduction. The number of chromosomes needed for fertility would keep going up and up....... what I mean by this is, if the organism did not reduce its chromosome number to reproduce you would get a doubling of chromosomes in each generation. The 11 chromosomes in a sex cell, will combine with another sex cell, which will also have 11 chromosomes, to form the normal 22 chromosomes in a fully functionally body cell. The process of halving the chromosome number occurs through a process called meiosis in the gonads of the organism. Hope this helps.
2007-01-04 16:01:54 · answer #1 · answered by Brian J 1 · 0⤊ 0⤋
Chromosomes are paired because the toad gets one of each pair from each parent. During egg formation, the pairs of chromosomes are separated from each other in a process called meiosis, and the egg gets only 11 out of the original 22. Once the egg is fertilized by a sperm, the sperm chromosomes are added to the egg chromosomes, thus returning the chromosome number of the now fertilized egg back to 22. Meiosis and fertilization maintains the number of chromosomes in the toad to the original 22. This way chromosomes don't increase in number each generation.
2007-01-04 16:12:03 · answer #2 · answered by Dulce D 2 · 0⤊ 0⤋
Toad skin cells are diploid, they contain a full set of chromosomes. Toad eggs, from the female, are haploid, as the contain half the chromosomes in the sex cells; either egg or sperm, in this case. Meiosis is the process that is used to separate the chromosome set, which happens to contain half from the father, half from the mother. Meiosis splits the chromosomes into a set from the father and a set from the mother; simply put.
2007-01-04 15:44:30 · answer #3 · answered by Anonymous · 0⤊ 0⤋
11 chromosomes from mom, 11 chromosomes from dad- 11 +11 = 22. The frog's body cells have 22 chromosomes, it's sperm/egg will have 11 so when the frog knocks up another frog the babies will have 22 also.
2007-01-04 16:04:26 · answer #4 · answered by Anonymous · 0⤊ 0⤋
But what?
2007-01-04 15:26:56 · answer #5 · answered by The Oliver 3 · 1⤊ 1⤋