Egg cell

The egg (Latin ovum, plural: ova ) or oocyte ( gr Oos, egg; Cytos cell) is the female germ cell bisexual beings. It serves the generative propagation by oogamy and contains all the genetic traits of the female organism that are passed on to the offspring. Egg cells are haploid cells and contain only one set of chromosomes.

While the male gamete, such as sperm, only the nuclear DNA in the formation of the zygote contributes provides the egg is usually the general cellular environment such as the cytoplasm and organelles present therein.

Mitochondria and plastids ( in plants ) also contain DNA, the most purely maternal ( mother's side) is inherited.

Plant

When plants are referred to as the ova unbegeißelten female gametes. They are substantially greater than the male gametes ( Anisogamie ) usually. In the seed plants, the eggs are in the ovule. The name was taken from the egg in zoology botany.

Vertebrates

Ova arise in vertebrates by two maturation divisions in the oogenesis in the ovary of diploid primordial germ cells ( reduction, then Äquationsteilung see also meiosis). Only by merging with a male germ cell zygote they reach a diploid and thus capable of dividing state. An exception is parthenogenesis, the development of an organism from an unfertilized egg. Human oocyte can be seen having a diameter from 0.11 to 0.14 mm, just with the naked eye.

People

The egg cell of humans and other mammals was discovered in 1827 by Karl Ernst von Baer.

While for decades assumed that women are born with only a certain number of eggs, and that they would be infertile after their consumption, reported U.S. researchers in early 2012 that eggs are producing stem cells in female ovaries.

Demarcation

The egg is an early stage of self- development ( ontogeny ) of a hurry ing animal ( Ovipars ). It contains in addition to the nucleus, also called egg, nutrients, and a protective shell ( " bowl ").