Ovule
See also: Ovule (homonymy)
The ovule is the sexual cell (or Gamète) produced by the Femelle S. Like all the gamètes, the ovule is Haploïde, it contains half of the Chromosome S of the mother. At the woman, the ovule is fertilizable only during 24 hours at the time of its descent in the horn after expulsion of the ovary.
At many species, like the Mammalian S, the pair of chromosomes specific to the females being pair XX (double X), an ovule can thus contain only X chromosomes. Consequently, it is the Spermatozoïde male which will determine the sex of the Zygote, the cell resulting from the Fécondation. If the male transmits a Y chromosome, then the result will be a male (XY). If in fact X is transmitted, then it will be a female (XX).
At the majority of the Poisson S and Amphibians, fecundation proceeds in an external way in the aquatic environment. What lays the females is in fact of the ovules suitable for meet the Spermatozoïde S contained in the “seed” that the male individuals also have slackening in water. In the language running, one speaks however and improperly about “fish eggs” whereas they are still ovules. The Caviar is thus made of ovules of Esturgeon!
At the plants, the gamète female door the name of Oosphere, the ovule term being reserved with the macrosporangium Spermaphytes (see Ovule (botanical)).
See too
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