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The male gametophyte will develop via one or two rounds of mitosis inside the anther. This creates a 2 or 3 celled male gametophyte which becomes known as the pollen grain once dehiscing occurs. [18] One cell is the tube cell, and the remaining cell/cells are the sperm cells. [19]
Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes.Depending on the biological life cycle of the organism, gametogenesis occurs by meiotic division of diploid gametocytes into various gametes, or by mitosis.
The result is a multi-cellular haploid organism, called the gametophyte (because it produces gametes at maturity). [17] When it reaches maturity, the gametophyte produces one or more gametangia (singular: gametangium) which are the organs that produce haploid gametes. At least one kind of gamete possesses some mechanism for reaching another ...
In the brown alga Fucus, all four egg cells survive oogenesis, which is an exception to the rule that generally only one product of female meiosis survives to maturity. In plants, oogenesis occurs inside the female gametophyte via mitosis. In many plants such as bryophytes, ferns, and gymnosperms, egg cells are formed in archegonia.
The resulting zygote develops into an embryo, while the triploid endosperm (one sperm cell plus two female cells) and female tissues of the ovule give rise to the surrounding tissues in the developing seed. The ovary, which produced the female gametophyte(s), then grows into a fruit, which surrounds the seed(s).
The gametophyte is the multicellular structure (plant) that is haploid, containing a single set of chromosomes in each cell. The gametophyte produces male or female gametes (or both), by a process of cell division, called mitosis. In vascular plants with separate gametophytes, female gametophytes are known as mega gametophytes (mega=large, they ...
The sperm of plants that reproduce using spores are formed by mitosis in an organ of the gametophyte known as the antheridium and the egg cells by mitosis in a flask-shaped organ called the archegonium. [16] Plant sperm cells are their only motile cells, often described as flagellate, but more correctly as ciliate. [17]
This results in a mature haploid ovum and the release of a polar body. [22] The nucleus of the oocyte is called a pronucleus in this process, to distinguish it from the nuclei that are the result of fertilization. Drawing of an ovum. The sperm's tail and mitochondria degenerate with the formation of the male pronucleus. This is why all ...