| 释义 |
pronucleus
pro·nu·cle·us P0596200 (prō-no͞o′klē-əs, -nyo͞o′-)n. pl. pro·nu·cle·i (-klē-ī′) The haploid nucleus of a sperm or egg before fusion of the nuclei in fertilization.
pro·nu′cle·ar adj.pronucleus (ˌprəʊˈnjuːklɪəs) n, pl -clei (-klɪˌaɪ) (Biology) the nucleus of a mature ovum or spermatozoan before fertilization pronuclear adjpro•nu•cle•us (proʊˈnu kli əs, -ˈnyu-)
n., pl. -cle•i (-kliˌaɪ) the haploid nucleus of either the sperm or ovum that unites with the opposite-sex nucleus during fertilization. [1875–80] Thesaurus| Noun | 1. | pronucleus - the nucleus of the ovum or sperm after fertilization but before they fuse to form the nucleus of the zygotecell nucleus, karyon, nucleus - a part of the cell containing DNA and RNA and responsible for growth and reproduction |
Pronucleus
pronucleus[prō′nü·klē·əs] (cell and molecular biology) One of the two nuclear bodies of a newly fertilized ovum, the male pronucleus and the female pronucleus, the fusion of which results in the formation of the germinal (cleavage) nucleus. Pronucleus the haploid nucleus of a sex cell, or gamete. During fertilization, the diploid nucleus of the zygote, or synkaryon, is formed by the fusion of two pronuclei; the chromosome sets of both pronuclei are joined in the synkaryon. In multicellular organisms and a number of protozoans that are anisogamous, there are female and male pronuclei. The female pronucleus is the nucleus of a mature egg cell, or macro-gamete. The male pronucleus is formed by the swelling of the nucleus of a spermatozoid, or microgamete, after it has become embedded in the cytoplasm of an egg cell. In isogamous unicellular organisms, the fusing pronuclei, like the gametes themselves, are morphologically indistinguishable. During autogamy, pronuclei that have been formed in the same cell fuse; they are usually sister nuclei. During conjugation in infusorians, two pronuclei form in each partner—a stationary pronucleus and a migrating pronucleus. There is first an exchange of migrating pronuclei between partners through a cytoplasmic bridge, which is followed by the fusion of the pronuclei in each of the partners. pronucleus
pronucleus [pro-noo´kle-us] the haploid nucleus of a germ cell.female pronucleus the haploid nucleus of the fully mature oocyte, which loses its nuclear envelope and liberates its chromosomes to meet the synapsis with those from the male pronucleus.male pronucleus the nuclear material of the head of a spermatozoon, after it has penetrated the oocyte and acquired a pronuclear membrane.pro·nu·cle·us, pl. pro·nu·cle·i (prō-nū'klē-ŭs, -klē-ī), 1. One of a pair of nuclei undergoing fusion in karyogamy. 2. In embryology, the nuclear material of the head of the sperm (male pronucleus) or of the oocyte (female pronucleus), after the oocyte has been penetrated by the sperm; each pronucleus normally carries a haploid set of chromosomes, so that the merging of the pronuclei in fertilization reestablishes diploidy. pronucleus (prō-no͞o′klē-əs, -nyo͞o′-)n. pl. pronu·clei (-klē-ī′) The haploid nucleus of a sperm or egg before fusion of the nuclei in fertilization.
pro·nu′cle·ar adj.pro·nu·cle·us, pl. pronuclei (prō-nū'klē-ŭs, -ī) 1. One of a pair of nuclei undergoing fusion in karyogamy. 2. embryology The nuclear material of the head of the sperm (male pronucleus) or of the oocyte (female pronucleus), after the oocyte has been penetrated by the sperm; each pronucleus normally carries a haploid set of chromosomes, so that the merging of the pronuclei in fertilization reestablishes the diploidy. pronucleus
Related to pronucleus: Female pronucleusWords related to pronucleusnoun the nucleus of the ovum or sperm after fertilization but before they fuse to form the nucleus of the zygoteRelated Words- cell nucleus
- karyon
- nucleus
|