| P site | <molecular biology> The peptidyl tRNA binding site on the ribosome, the one to which the growing chain is attached, the incoming aminoacyl tRNA attaches to the A site. (18 Nov 1997) |
|---|---|
| secondary site | A second site in which cancer is found. Example: cancer in the lymph nodes near the breast is a secondary site. (09 Oct 1997) |
| sequence tagged site | <molecular biology> Short (200 to 500 base pairs) DNA sequence that has a single occurrence in the human genome and whose location and base sequence are known. Detectable by PCR, sequence tagged sites are useful for localising and orienting the mapping and sequence data reported from many different laboratories and serve as landmarks on the developing physical map of the human genome. Expressed sequence tags are sequence tagged sites derived from cDNAs. (11 Jun 1998) |
| sequence-tagged site map | A map representing the order and spacing of sequence-tagged sites within a stretch of DNA. (05 Mar 2000) |
| hypersensitive site | <molecular biology> A short segment of DNA which is especially prone to being cleaved by endonuclease enzymes like DNase. These sites tend to be within gene promoter regions. (11 Jan 1998) |
| site | The spatial confines of a particular project. (09 Oct 1997) |
| site-directed mutagenesis | <molecular biology> Any of several methods used to create specific alterations in a gene. (09 Oct 1997) |
| site potential tree | A tree that has attained the average maximum height possible given site conditions where it occurs. (05 Dec 1998) |
| site preparation | Various treatments applied to a harvested area to promote regeneration of the site. (05 Dec 1998) |
| site-specific DNA-methyltransferase (adenine-specific) | <enzyme> An enzyme responsible for producing a species-characteristic methylation pattern on adenine residues in a specific short base sequence in the host cell DNA. The enzyme catalyses the methylation of DNA adenine in the presence of s-adenosyl-l-methionine to form DNA containing 6-methylaminopurine and s-adenosyl-l-homocysteine. Registry number: EC 2.1.1.72 (12 Dec 1998) |
| site-specific DNA methyltransferase (cytosine-specific) | <enzyme> An enzyme responsible for producing a species-characteristic methylation pattern on cytosine residues in a specific short base sequence in the host cell's DNA. The enzyme catalyses the methylation of DNA cytosine in the presence of s-adenosyl-l-methionine to form s-adenosyl-l-homocysteine and DNA containing 5-methylcytosine. Registry number: EC 2.1.1.73 (12 Dec 1998) |
| site-specific mutagenesis | <cell culture, molecular biology> An in vitro technique in which an alteration is made at a specific site in a DNA molecule, which is then reintroduced into a cell. Various techniques are used, for the cell biologist, a very powerful approach to determining which parts of a protein or nucleotide sequence are critical to function. (18 Nov 1997) |
| site specific mutation | An alteration of the structure of a gene at a specific sequence, usually referring to experimentally produced changes in gene sequence. (05 Mar 2000) |
| site-specific recombination | <molecular biology> A type of recombination that occurs between two specific short DNA sequences present in the same or in different molecules. An example is the integration and excision of _ prophage. (18 Nov 1997) |
| special aquatic site | Those sites identified in 40 CRF 230, Subpart E (i.e., sanctuaries and refuges, wetlands, mud flats, vegetated shallows, coral reefs, and riffle and pool complexes). They are geographic areas, large or small, possessing special ecological characteristics of productivity, habitat, wildlife protection, or other important and easily disrupted ecological values. These areas are generally recognised as significantly influencing or positively contributing to the general overall environmental health or vitality of the entire ecosystem of a region. Source: Environmental Protection Agency, 40 CFR |