Ectocarpus siliculosus, female gamete surrounded by male gametes.
Usually, however, only one of the fusing cells is a zoogamete, the other gamete being a much larger resting cell.
This view is still maintained by those who differentiate two acts of fertilization within the embryo-sac, and regard that of the egg by the first male-cell, as the true or generative fertilization, and that of the polar nuclei by the second male gamete as a vegetative fertilization which gives a stimulus to development in correlation with the other.
In Sirogonium there is cell-division in the parent-cell prior to conjugation; and as two segments are cut off in the case of the active gamete, and only one in the case of the passive gamete, there is a corresponding difference of size, marking another step in the sexual differentiation.
In such a case the zoogamete is male, is called an antherozoid or spermatozoid, and arises in an antheridium; the larger gamete is an oosphere and arises in an oogonium.
From a comparison of those Euchlorophyceae which have been most closely investigated, it appears probable that sexual reproductive cells have in the course of evolution arisen as the result of specialization among asexual reproductive cells, and that in turn oogamous reproduction has arisen as the result of differentiation of the two conjugating cells into the smaller male gamete and the larger male gamete.
a, antherozoids, b, a female gamete.
Similarly, other fertility techniques such as gamete intrafallopian transfer (GIFT) and zygote intrafallopian transfer (ZIFT) are also more likely to result in multiple gestations.
gamete donation of course is not something that can be entered into lightly.
In flowering plants, anther s produce pollen which contains male gametes, and the embryo sac within the ovary contains a female gamete.
gamete cell contains 23 chromosomes.
Gamete: The male sperm or female egg which fuse together to form a zygote.
This is the first time that the UK government has put resources behind a national program to recruit gamete donors.
In addition, 60 units could also represent a gamete about to divide to form 2 gametes.
gamete donor anonymity practice in April.
gamete fusion and fertilization in animals, double fertilization in plants.
oviduct physiology, pregnancy, gamete biology and immunology.
In the formation of the female gamete in plants, how do the polar bodies end up being diploid?
gamete formation and fertilization should be presented to establish links between generations.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.