| 翻訳と辞書 |
gamete
A gamete (from Ancient Greek γαμετή ''gamete'' from gamein "to marry"〔(【引用サイトリンク】url=http://www.etymonline.com/index.php?term=gamete&allowed_in_frame=0 )〕) is a cell that fuses with another cell during fertilization (conception) in organisms that sexually reproduce. In species that produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gamete—called an ovum (or egg)—and a male produces the smaller tadpole-like type—called a sperm. This is an example of anisogamy or heterogamy, the condition in which females and males produce gametes of different sizes (this is the case in humans; the human ovum has approximately 100,000 times the volume of a single human sperm cell〔Marshall, A. M. 1893. ''Vertebrate embryology: a text-book for students and practitioners''. GP Putnam's Sons.〕〔Yeung, C., M. Anapolski, M. Depenbusch, M. Zitzmann, and T. Cooper. 2003. "Human sperm volume regulation. Response to physiological changes in osmolality, channel blockers and potential sperm osmolytes." ''Human Reproduction'' 18:1029.〕). In contrast, isogamy is the state of gametes from both sexes being the same size and shape, and given arbitrary designators for mating type. The name gamete was introduced by the Austrian biologist Gregor Mendel. Gametes carry half the genetic information of an individual, one ploidy of each type, and are created through meiosis.
==Dissimilarity==
In contrast to a gamete, the diploid somatic cells of an individual contain one copy of the chromosome set from the sperm and one copy of the chromosome set from the egg cell; that is, the cells of the offspring have genes expressing characteristics of both the ''father'' and the ''mother''. A gamete's chromosomes are not exact duplicates of either of the sets of chromosomes carried in the diploid chromosomes, and often undergo random mutations resulting in modified DNA (and subsequently, new proteins and phenotypes).
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「gamete」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|