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Human egg cell. The egg cell or ovum (pl.: ova) is the female reproductive cell, or gamete, [1] 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).
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]
Many of the features found in human ovaries are common to all vertebrates, including the presence of follicular cells, tunica albuginea, and so on. However, many species produce a far greater number of eggs during their lifetime than do humans, so that, in fish and amphibians, there may be hundreds, or even millions of fertile eggs present in ...
In most plant species, an individual has both male and female sex organs (a hermaphrodite). [24] The life cycle of land plants involves alternation of generations between a sporophyte and a haploid gametophyte. [25] The gametophyte produces sperm or egg cells by mitosis. The sporophyte produces spores by meiosis, which in turn develop into ...
Alternatively, as in flowering plants, conifers and gnetophytes, neither of the gametes are flagellated. In these groups, the male gametes are non-motile cells within pollen grains, and are delivered to the egg cells by means of pollen tubes. In the red alga Polysiphonia, non-motile eggs are fertilized by non-motile sperm.
They are small plants found growing in moist locations and like ferns, have motile sperm with flagella and need water to facilitate sexual reproduction. These plants start as a haploid spore that grows into the dominant gametophyte form, which is a multicellular haploid body with leaf-like structures that photosynthesize. Haploid gametes are ...
In many plants such as bryophytes, ferns, and gymnosperms, egg cells are formed in archegonia. In flowering plants, the female gametophyte has been reduced to an eight-celled embryo sac within the ovule inside the ovary of the flower. Oogenesis occurs within the embryo sac and leads to the formation of a single egg cell per ovule.
The female gonad, the ovary, produces egg cells. Both of these gametes are haploid cells. Some hermaphroditic animals (and some humans — see Ovotesticular syndrome) have a type of gonad called an ovotestis.