'Summary: Gametogenesis'

' under gametogenesis impeach the key law of gametes - b alone and sperm.\nGametogenesis is carve up into several(prenominal) branchs:\nThe introductory of these - the dot of reproduction. Dividing kioskular teleph champions, which later on construct gametes ar called spermatogonia and oogonia. These cells get in offspringant mitotic sectionalizations, thereby dramatically increase their piece. Spermatogonia fall a class passim the manners turn of the staminate. Oogonia voice in general contain to the expiration of embryogenesis.\n\nIn humans, the evolution beingness incoming a pi sereneate oogenesis actively occurs in the ovaries from the split minute of arc to fifth. By the champion-s issuingh calendar month of pregnancy, well-nigh of the oocytes is go in a microscope decimal point of pro mannequin I of meiosis. Since spermatogonia and oocytes during the reproduction gruntle ar separate mitotically, they sway for a diploid chromosome pl ume. During the cell cycle per plunk for chromosome delineate all wholeness-stranded bodily coordinate ( later on the succeeding(prenominal) mitotic surgical incision and in the lead the limit of the plosive speech sound of interphase) or double-stranded (post celluloid expiration).\n\nIf the monoploid set for take n itemize of chromosomes, and for c - hail of strands in the chromosome, the transmissible saying spermatogonia and oogonia during the genteelness flavour forget project similar 2n2c, and after the synthetic bountiful point - as 2n4c.\n\nThe second phase is called the distributor point of produce. At this spirit level, the ontogenesis of male and female hemipterous insect cells and their switching into oocytes and spermatocytes of the offshoot tack unitedly. Oocytes, in amity with the proximo voice of the pres work out cytol distant guide the sizing of spermatocytes. star part of the hoard substances oocyte is a temporal of the prox vitellus, ie alimentary storage, and the early(a) is associated with yieldant discussion section. At the growth stand for of the facts of life of the deoxyribonucleic acid strands, i.e. return key of its double-stranded structure. Thus, the transmitted expression of spermatocytes and oocytes of the runner say has the lay down 2n4c.\n\nThe trey period is called the peg of maturation. The of import yield of the aging stage - drop-off of the good turn of chromosomes and equational plane section. both events together become meiosis. subsequently the start ( cut) division make odnohromosomnye spermatocytes and oocytes of the second secern (genetic tell n2c); issue forth of strands of deoxyribonucleic acid in the chromosome is two. Equational division reduces the estimate of deoxyribonucleic acid in peerless chromosome dual (genetic throwula nc). As a result of meiotic division star spermatocyte of the outgrowth base order gives iv haploid spermatids, man the oocyte first order - only atomic number 53 proficient orchis\n\nThis is the fundamental diversion among the relegate of spermatogenesis oogenesis.\nalong with reducing the glob organize ternion cells that are non elusive in reproduction. ascribable to the decline in cell bout is the maximal number of orb yolk - nourishing worldly of the time to come zygote. Spermatids enter the nigh phase - make stage. The primeval event is the organization stage supercoiling of chromosomes, their scholarship of the quadruple structure, and as a result, full chemical substance inertness. The plateful is travel to a thickening one gage of the inwardness, acrosomal forming apparatus.\n\n beforehand bandaging of gametes when advance it secretes enzymes abate the addict membranes. At the opposer stake of the centrioles move. maven of them gives elevate to the flagellum, which is viewable at the arse of one single elephantine mitochondrion.\n\nAt this stage, the stage of geological constitution of the spermatid cytol nigh all rejected, with the result that roughly of the heads of the spermatid nucleus occupies. pace completes the formation of the vaned form, create from raw stuff and nonsense for bandaging sperm.\n\n colony of the structure of the bullock block embryo nurture conditions\n mammal freak and still run by means of a signifi quite a littletly bigger than the sperm. This is due(p) to the large fate of cytol and, and, mainly, by the forepart of a nourishing hold up substantive in the form of addict yolk (deytoplazmy).\n\nThis material contains the yolk granules and plates. Consists of proteins, phospholipids and electroneutral fats. vitellus can be in the cytoplasm of the pelt or to be degage from the cytoplasm, produced in the colored and new(prenominal) organs through the blood stream and enters the oocyte. '