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  2. Human reproduction - Wikipedia

    en.wikipedia.org/wiki/Human_reproduction

    During sexual intercourse, sperm cells are ejaculated into the vagina through the penis, resulting in fertilization of an ovum to form a zygote. [1] While normal cells contain 46 chromosomes (23 pairs), gamete cells contain only half that number, and it is when these two cells merge into one combined zygote cell that genetic recombination occurs.

  3. Origin and function of meiosis - Wikipedia

    en.wikipedia.org/wiki/Origin_and_function_of_meiosis

    It is the stage of the life cycle when a cell gives rise to haploid cells each having half as many chromosomes as the parental cell. Two such haploid gametes, ordinarily arising from different individual organisms, fuse by the process of fertilization, thus completing the sexual cycle.

  4. Reproduction - Wikipedia

    en.wikipedia.org/wiki/Reproduction

    Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. There are two forms of reproduction: asexual and sexual. In asexual reproduction, an organism can reproduce without the involvement of another organism.

  5. Cell cycle - Wikipedia

    en.wikipedia.org/wiki/Cell_cycle

    The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.

  6. Sexual reproduction - Wikipedia

    en.wikipedia.org/wiki/Sexual_reproduction

    Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete (haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes . [1]

  7. Asexual reproduction - Wikipedia

    en.wikipedia.org/wiki/Asexual_reproduction

    Asexual reproduction is the primary form of reproduction for single-celled organisms such as archaea and bacteria. Many eukaryotic organisms including plants , animals , and fungi can also reproduce asexually. [ 1 ]

  8. Cell theory - Wikipedia

    en.wikipedia.org/wiki/Cell_theory

    Cells are the basic unit of structure in all living organisms and also the basic unit of reproduction. Cell theory has traditionally been accepted as the governing theory of all life , [ 1 ] but some biologists consider non-cellular entities such as viruses living organisms [ 2 ] and thus disagree with the universal application of cell theory ...

  9. Cell division - Wikipedia

    en.wikipedia.org/wiki/Cell_division

    Due to their structural differences, eukaryotic and prokaryotic cells do not divide in the same way. Also, the pattern of cell division that transforms eukaryotic stem cells into gametes (sperm cells in males or egg cells in females), termed meiosis, is different from that of the division of somatic cells in the body. Cell division over 42.