As of 2019, there are about eight monkey sterilization centers spread across the state, where macaques brought in by trappers are sterilized using laser vasectomies in males and endoscopic thermocauteric tubectomies in females, Satish K. Gupta, emeritus scientist specializing in Reproductive Cell Biology at the National Institute of Immunology, New Delhi, said in an email to Gizmodo.
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A gonidium (plural gonidia) is an asexual reproductive cell or group of cells, especially in algae.
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Programmed theories of aging posit that aging is adaptive, normally invoking selection for evolvability or group selection. The reproductive-cell cycle theory suggests that aging is regulated by changes in hormonal signaling over the lifespan.
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Diagram of a human sperm cell Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, "female" reproductive cell and a smaller, "male" one). Animals produce motile sperm with a tail known as a flagellum, which are known as spermatozoa, while some red algae and fungi produce non-motile sperm cells, known as spermatia. Flowering plants contain non-motile sperm inside pollen, while some more basal plants like ferns and some gymnosperms have motile sperm. Sperm cells form during the process known as spermatogenesis, which in amniotes (reptiles and mammals) takes place in the seminiferous tubules of the testes.
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Megaloschizonts and the smaller schizonts are the part of the life cycle that takes place inside the infected host organism and operates as an asexually reproductive cell. Megaloschizonts appear as grey-white nodules found in the smooth muscle of major organs, such as the heart, liver, lung or spleen.
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A macronucleus (formerly also meganucleus) is the larger type of nucleus in ciliates. Macronuclei are polyploid and undergo direct division without mitosis. It controls the non-reproductive cell functions, such as metabolism. During conjugation, the macronucleus disintegrates, and a new macronucleus is formed by karyogamy of the micronuclei.
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Previous experimentation has found that PROSER2 interacts with several other proteins including: STK24, ESR2, POT1, ACTB, and EPS8.STRING 10: Known and Predicted Protein-Protein Interactions. These interacting proteins are involved in control of apoptosis, reproductive cell differentiation, telomere maintenance, cell integrity, and cell cycle progression, respectively. These interactions identify PROSER2 as a gene heavily involved in the regulation of cell differentiation and apoptosis.
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Rhombozoa, or dicyemid mesozoans, are found in the nephrid tracts of squid and octopuses. They range from a few millimeters long with twenty to thirty cells that include anterior attachment cells and a long central reproductive cell called an axial cell. This axial cell may develop asexually into vermiform juveniles or it may produce eggs and sperm that self-fertilize to produce a ciliated infusiform larva. There are three genera: Dicyema, Pseudicyema and Dicyemennea.
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The condition 48,XXYY is not inherited; it usually occurs as a random event during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. In 48,XXYY syndrome, the extra sex chromosomes almost always come from a sperm cell. Nondisjunction may cause a sperm cell to gain two extra sex chromosomes, resulting in a sperm cell with three sex chromosomes (one X and two Y chromosomes).
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Triporate pollen of Oenothera speciosa Pollen of Lilium auratum showing single sulcus (monosulcate) Arabis pollen has three colpi and prominent surface structure. Pollen microspores of Lycopersicon esculentum at coenocytic tetrad stage of development observed through oil immersion microscope; the chromosomes of what will become four pollen grains can be seen. Apple pollen under microscopy Pollen itself is not the male gamete. Each pollen grain contains vegetative (non-reproductive) cells (only a single cell in most flowering plants but several in other seed plants) and a generative (reproductive) cell.
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Human egg cell The egg cell, or ovum (plural ova), is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, "female" gamete and a smaller, "male" one). The term is used when the female gamete is not capable of movement (non-motile). If the male gamete (sperm) is capable of movement, the type of sexual reproduction is also classified as oogamous. When egg and sperm fuse during fertilisation, a diploid cell (the zygote) is formed, which rapidly grows into a new organism.
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The macronucleus controls non-reproductive cell functions, expressing the genes needed for daily functioning. The micronucleus is the generative, or germline nucleus, containing the genetic material that is passed along from one generation to the next. In the asexual fission phase of growth, during which cell divisions occur by mitosis rather than meiosis, clonal aging occurs leading to a gradual loss of vitality. In some species, such as the well studied Paramecium tetraurelia, the asexual line of clonally aging paramecia loses vitality and expires after about 200 fissions if the cells fail to undergo meiosis followed by either autogamy (self-fertilization) or conjugation (outcrossing) (see aging in Paramecium).
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Cell division in prokaryotes (binary fission) and eukaryotes (mitosis and meiosis) Cell division is the process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle. In eukaryotes, there are two distinct types of cell division: a vegetative division, whereby each daughter cell is genetically identical to the parent cell (mitosis), and a reproductive cell division, whereby the number of chromosomes in the daughter cells is reduced by half to produce haploid gametes (meiosis). In cell biology, mitosis (/maɪˈtoʊsɪs/) is a part of the cell cycle, in which, replicated chromosomes are separated into two new nuclei.
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