Diploïde
A biological cell is diploïde (of the Greek diploos , double and eidos , in form of) when the Chromosome S which it contains are present by paires ( 2n chromosomes). the concept is generally to oppose to Haploïde, term indicating the cells with chromosomes in simple specimen ( N chromosomes) .
An organization or part of organization is known as diploïdes when its cells are themselves diploïdes.
These definitions relate to only the organizations Eucaryotes (animal protists, , vegetable, mushrooms), which have truths chromosomes. It thus excludes for example the Bactérie S which do not have a core and have chromosomes of a particular type.
The reproduction sexuée which implies a genetic exchange brings into play mechanisms of reduction (Méiose) and of increase (Fécondation) in the repetition of the chromosomes (Ploïdie). The life cycle of an organization eucaryote thus includes/understands necessarily an alternation of stages with different levels of chromosomal repetition: one speaks about alternation of phases (see Life cycle (biology)).
At the human ones, and the majority of the animals, the phase diploïde ( 2n ) are very dominant. The organization (the body) develops entirely with cells which contain each one the chromosomes in double specimen. The Haploid phase ( N ), as for it, relates to only the formation of the Gamète S: Spermatozoon or Ovule. At the foams, at some Alga S, the diagram is reversed: the phase Diploïde ( 2n ) accompanies only very briefly fecundation. The plant develops following the Méiose, in form Haploïde ( N ).
More
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to see the article on the Ploïdie
- Life cycle (biology)
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