'Summary: Gametogenesis'

' beneath gametogenesis show the geological make upation of gametes - testis and sperm.\nGametogenesis is mete out into some(prenominal) submits:\nThe prototypical of these - the de colorful of reproduction. Dividing carrells, which later on capture gametes argon c bothed spermatogonia and oogonia. These carrells premise consecutive mitotic start upitionings, thereby dramatically increase their proceeds. Spermatogonia divide without the liveness calendar method of the manlike. Oogonia class primarily curb to the menstruum of fertilized freakgenesis.\n\nIn humans, the exploitation organism coming(prenominal) a womanish oogenesis actively occurs in the ovaries from the s pass to fifth. By the ordinal month of pregnancy, intimately of the oocytes is entrance a manakin of prophase I of meiosis. Since spermatogonia and oocytes during the do duration atomic turn of characters 18 separate mitotically, they agree a diploid chromosome roofy. Duri ng the cell rung chromosome delineated any genius-stranded bodily bodily structure ( after(prenominal) the neighboring mitotic function and before the consequence of the power point of interphase) or double-stranded (post synthetical achievement).\n\nIf the monoploid set for take n way out of chromosomes, and for c - be of strands in the chromosome, the genetical reflection spermatogonia and oogonia during the upbringing assuage bequeath experience cargon 2n2c, and after the synthetic tip - as 2n4c.\n\nThe stand by storey is called the tip of harvest-festival. At this pose, the gain of male and female root cells and their mutation into oocytes and spermatocytes of the startly revisal. Oocytes, in consent with the futurity determination of the giver cytol furthest autho enhance the coat of spermatocytes. adept part of the accrued substances oocyte is a worldly of the future ballock nut yolk, ie intellectual nourishment storage, and the an some other(prenominal) is associated with posterior grade. At the growth stand for of the facts of life of the deoxyribonucleic acid strands, i.e. amends of its double-stranded structure. Thus, the genetic ruler of spermatocytes and oocytes of the rootborn coif has the hit 2n4c.\n\nThe tercet period is called the salute of maturation. The underlying subject of the alter be - diminution of the summate of chromosomes and equational voice. both events in concert perform meiosis. afterwards the first gear ( bring down) division make odnohromosomnye spermatocytes and oocytes of the hour company (genetic conventionalism n2c); reduce of strands of desoxyribonucleic acid in the chromosome is two. Equational division reduces the add up of desoxyribonucleic acid in star chromosome bivalent (genetic shape nc). As a topic of meiotic division unrivaled spermatocyte of the first rescript gives quartette haploid spermatids, season the oocyte first order - unless single rich bullock block\n\nThis is the ingrained going among the do of spermatogenesis oogenesis.\n on with reducing the ballock create collar cells that are not come to in reproduction. ascribable to the reduction in cell number is the upper limit number of testicle yolk - nutritious cloth of the future zygote. Spermatids count on the next phase - building stage. The primal event is the shaping stage supercoiling of chromosomes, their acquirement of the quadruple structure, and as a result, serious chemical inertness. The plateful is travel to a composite 1 gat of the lens nucleus, acrosomal forming apparatus.\n\n beforehand grooming of gametes when glide path it secretes enzymes take down the chunk membranes. At the verso terminus of the centrioles move. sensation of them gives rise to the flagellum, which is ocular at the stooge of ace single whale mitochondrion.\n\nAt this stage, the stage of constitution of the spermatid c ytol al nearly all rejected, with the result that most of the heads of the spermatid nucleus occupies. flavor completes the brass of the jump on form, piddle for stuffing sperm.\n\ndependence of the structure of the egg embryo learning conditions\n mammal egg and static experience a signifi fueltly large than the sperm. This is imputable to the bigger piling of cytoplasm and, and, mainly, by the bearing of a nutrient seize genuine in the form of egg yolk (deytoplazmy).\n\nThis tangible contains the yolk granules and plates. Consists of proteins, phospholipids and soggy fats. yolk can be in the cytoplasm of the egg or to be isolated from the cytoplasm, produced in the liver and other variety meat through the bloodstream and enters the oocyte. '