Birgid Schlindwein's
Hypermedia Glossary Of Genetic Terms
Search Results
Birgid Schlindwein'sHypermedia Glossary Of Genetic TermsSearch Results |
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| Restriction enzyme cutting site | A specific nucleotide sequence of DNA at which a particular restriction enzyme cuts the DNA. Some sites occur frequently in DNA (e.g., every several hundred base pairs), others much less frequently (rare-cutter; e.g., every 10,000 base pairs). |
| Nucleotide | A subunit of DNA or RNA consisting of a nitrogenous base (purine in adenine and guanine, pyrimidine in thymine, or cytosine for DNA and uracil cytosine for RNA), a phosphate molecule, and a sugar molecule (deoxyribose in DNA and ribose in RNA). Depending on the sugar the nucleotides are called deoxyribonucleotides or ribonucleotides. Thousands of nucleotides are linked to form a DNA or RNA molecule. See also base pair. |
| Base sequence | The order of nucleotide bases in a DNA molecule. Length is usually defined as the number of base pairs. Cf. sequence, DNA sequence. |
| Restriction enzyme | A bacterially derived protein that recognizes specific, short nucleotide sequences and cuts DNA at those sites. Bacteria contain over 400 such enzymes that recognize and cut over 100 different DNA sequences. See restriction enzyme cutting site and endonuclease. |
| Base pair (bp) | Two nitrogenous (purine or pyrimidine) bases (adenine and thymine or guanine and cytosine) held together by weak hydrogen bonds. Two strands of DNA are held together in the shape of a double helix by the bonds between base pairs. The number of base pairs is often used as a measure of length of a DNA segment, eg 500 bp. |