Cell Cycle by Hamed AlShammari

Meiosis

hamedalshammari — 2016-10-12 16:23:10 UTC

Meiosis is a process of nuclear division that reduces the number of chromosomes in new cells to half the number in the original cell. Cells begin meiosis with a duplicate set of chromosomes, just as cells beginning mitosis do.Diploid (2n) cells that divide meiotically result in four haploid (1n) cells rather than two diploid (2n) cells because cells go through meiosis divide twice.

Meiosis I 1Interphase

hamedalshammari — 2016-10-12 16:25:57 UTC

1.G1 phase- Offspring cells cells grow to mature size
2.S phase- Dna synthesis
3. G2 phase- Cell prepares for cell division; spindle fibers and centrioles gather at poles of the cell

2. Prophase I

hamedalshammari — 2016-10-12 16:32:41 UTC

The copied DNA chromatin coils into chromatids. Sister chromatids bind together to make chromosomes. Homologous chromosomes line up next to each other. The Homologous chromosomes physically cross over. The nuclear membrane disappears.

3. Metaphase I

hamedalshammari — 2016-10-12 16:40:42 UTC

Homologous chromosomes are lined up in the middle of the cell. Spindle fibers from one pole attach to the centromere of one homologous chromosome.

4. Anaphase I

hamedalshammari — 2016-10-12 16:43:01 UTC

The homologous chromosomes are pulled apart. Independent assortment (the random separation of the chromosomes) results in genetic variation.

5. Telophase&Cytokinesis

hamedalshammari — 2016-10-12 16:45:18 UTC

The sets are now two haploid cells. The original cell produces two new cells, each containing one chromosome from each homologous pair. The new cells contain half the number of chromosomes of the original cell. Each new cell contains two copies (as chromatids), because the original cell copied its DNA before meiosis I