| spermatozoa | Mature male germ cells, the specific output of the testes. The spermatozoon is the generative element of the semen and serves to fertilise the ovum. It consists of a head (or nucleus), a neck, a middle piece, and a tail with an end piece. Spermatzoa, formed in the seminiferous tubules, are derived from spermatogonia, which first develop into spermatocytes, which, in turn, undergo meiosis to produce spermatids; the spermatids then differentiate into spermatozoa. (12 Dec 1998) |
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| spermatozoal | Spermatozoan Relating to spermatozoa. (05 Mar 2000) |
| spermatozoid | <biology> The male germ cell in animals and plants, the essential element in fertilization; a microscopic animalcule-like particle, usually provided with one or more cilia by which it is capable of active motion. In animals, the familiar type is that of a small, more or less ovoid head, with a delicate threadlike cilium, or tail. Called also spermatozoon. In plants the more usual term is antherozoid. Origin: Spermatozoon + Gr. Form. Source: Websters Dictionary (01 Mar 1998) |
| spermatozooid | <biology> A spermatozoid. Source: Websters Dictionary (01 Mar 1998) |
| spermatozoon | Mature sperm cell (male gamete). (18 Nov 1997) |
| spermaturia | <urology> The excretion of urine containing semen. Synonym: seminuria, spermaturia. (05 Mar 2000) |
| spermia | Plural of spermium. (05 Mar 2000) |
| spermicidal | Destructive to spermatozoa. Synonym: spermicidal. (05 Mar 2000) |
| spermicide | <pharmacology> An agent that is destructive to spermatozoa. (18 Nov 1997) |
| spermidine | <biochemistry> A polybasic amine. See: spermine. (18 Nov 1997) |
| spermidine acetylase | <enzyme> Froms monoacetylspermidine from acetyl-CoA and spermidine Registry number: EC 2.3.1.- (26 Jun 1999) |
| spermidine acetyltransferase | <enzyme> Involved in conversion of spermidine into putrescine; csat refers to n1-acetyltransferse; nsat refers to n8-acetyltransferase Registry number: EC 2.3.1.57 Synonym: spermidine-spermine n(1)-acetyltransferase, diamine acetyltransferase, csat transferase, nsat transferase, spermidine n(8)-acetyltransferase, spermidine n1-acetyltransferase, spermidine n8-acetyltransferase, putrescine n-acetyltransferase (26 Jun 1999) |
| spermidine synthase | <enzyme> An enzyme that catalyses the transfer of the propylamine moiety from 5'-deoxy-5'-s-(3-methylthiopropylamine)sulfonium adenosine to putrescine in the biosynthesis of spermidine. The enzyme has a molecular weight of approximately 73,000 kD and is composed of two subunits of equal size. Chemical name: S-Adenosylmethioninamine:putrescine 3-aminopropyltransferase Registry number: EC 2.5.1.16 (12 Dec 1998) |
| spermidium | Origin: Nl, fr. Gr. Seed. <botany> An achenium. Source: Websters Dictionary (01 Mar 1998) |
| spermiduct | Synonym: ductus deferens. Synonym: ejaculatory duct. (05 Mar 2000) |