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작성자 Georgianna 작성일25-09-30 02:08 조회8회 댓글0건본문
<p>In cellular biology, a somatic cell (from Ancient Greek σῶμα (sôma) 'body'), or vegetal cell, is any biological cell forming the body of a multicellular organism other than a gamete, germ cell, gametocyte or undifferentiated stem cell. Somatic cells compose the body of an organism and divide through mitosis. In contrast, gametes derive from meiosis within the germ cells of the germline and they fuse during sexual reproduction. Stem cells also can divide through mitosis, but are different from somatic in that they differentiate into diverse specialized cell types. In mammals, somatic cells make up all the internal organs, skin, bones, blood and connective tissue, while mammalian germ cells give rise to spermatozoa and ova which fuse during fertilization to produce a cell called a zygote, which divides and differentiates into the cells of an embryo. There are approximately 220 types of somatic cell in the human body. Theoretically, these cells are not germ cells (the source of gametes); they transmit their mutations, to their cellular descendants (if they have any), but not to the organism's descendants.</p><br/><br/><span style="display:block;text-align:center;clear:both"><iframe width="640" height="360" src="https://www.youtube.com/embed/sNCFDs0Tu1Y?rel=0&showinfo=0&cc_load_policy=1" frameborder="0" allowfullscreen title="Increase penile length? What's true and what's not - Urologist explains (c) by N/A"></iframe></span><p>However, in sponges, non-differentiated somatic cells form the germ line and, in Cnidaria, differentiated somatic cells are the source of the germline. Mitotic cell division is only seen in diploid somatic cells. Only some cells like germ cells take part in reproduction. The evolution of an immortal germline producing specialized somatic cells involved the emergence of mortality, and can be viewed in its simplest version in volvocine algae. Those species with a separation between sterile somatic cells and a germline are called Weismannists. <a href="https://www.renewableenergyworld.com/?s=Weismannist%20development">Weismannist development</a> is relatively rare (e.g., vertebrates, arthropods, Volvox), as many species have the capacity for <a href="https://git.changenhealth.cn/christenacak7">www.PrimeBoosts.com</a> somatic embryogenesis (e.g., land plants, most algae, and numerous invertebrates). Like all cells, somatic cells contain DNA arranged in chromosomes. If a somatic cell contains chromosomes arranged in pairs, it is called diploid and the organism is called a diploid organism. The gametes of diploid organisms contain only single unpaired chromosomes and are called haploid.</p><br/><br/><p>Each pair of chromosomes comprises one chromosome inherited from the father and one inherited from the mother. In humans, somatic cells contain 46 chromosomes organized into 23 pairs. By contrast, gametes of diploid organisms contain only half as many chromosomes. In humans, this is 23 unpaired chromosomes. When two gametes (i.e. a spermatozoon and an ovum) meet during conception, they fuse together, creating a zygote. Due to the fusion of the two gametes, a human zygote contains 46 chromosomes (i.e. 23 pairs). A large number of species have the chromosomes in their somatic cells arranged in fours ("tetraploid") or even sixes ("hexaploid"). Thus, Click here ----WebKitFormBoundaryL5hcdFdcQGzFBJWR--
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