Compare And Contrast Meosis And Meiosis

1022 Words 5 Pages
Larry Oliver
2 December 2016
EXSC 223
Assignment Four
1. Define Meiosis. Compare and contrast meiosis with mitosis.
Meiosis is the nuclear division process that reduces the chromosomal number by half and results in the formation of four haploid (n) cells; occurs only in certain reproductive organs. Mitosis has only one division consisting of prophase, metaphase, anaphase, and telophase, meiosis has two divisions each of the 4 phases listed. Also, meiosis has a synapsis of homologous chromosomes while mitosis does not. During daughter cell number and genetic composition, mitosis has two, each diploid cell is identical to the mother cell. While during meiosis this changes to 4 and each haploid cell contains half as many chromosomes as the mother cell and is inherently genetically different than the mother cell. Another difference is how the chromosomes align at the metaphase plate, during mitosis the chromosomes will align at the center,
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Then FSH and LH stimulate follicles to grow, mature, and secrete sex hormones. FSH effects the granulosa cells of vesicular follicles making them release estrogens, while LH makes thecal cells to release androgens in which the granulosa cells then convert to estrogens. As the estrogen levels rise, a negative feedback regulation on the hypothalamus and anterior pituitary kicks in stopping the release of FSH and LH. Also inhibin releases by the granulosa cells also stop release of FSH. Positive feedback stimulates gonadotropin release due to the high levels of estrogen in the blood. LH surges causes the follicle to rupture and the release of the secondary oocyte and the ruptured follicle then transforms into a corpus luteum. This causes production of large amounts of progesterone and some estrogens. Negative feedback then inhibits LH and FSH

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