Birgid Schlindwein's
Hypermedia Glossary Of Genetic Terms
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Birgid Schlindwein'sHypermedia Glossary Of Genetic TermsSearch Results |
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| 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. |
| Protein | A large molecule composed of one or more chains of amino acids in a specific order; the order is determined by the base sequence of nucleotides in the gene coding for the protein. Proteins are required for the structure, function, and regulation of the bodys cells, tissues, and organs, and each protein has unique functions. Examples are hormones, enzymes, and antibodies. |
| 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. |
| Deoxyribonucleic acid (DNA) | The molecule that encodes genetic information. DNA is a double-stranded molecule held together by weak bonds between base pairs of nucleotides. The four nucleotides in DNA contain the bases: adenine (A), guanine (G), cytosine (C), and thymine (T). In nature, base pairs form only between A and T and between G and C; thus the base sequence of each single strand can be deduced from that of its partner. |
| Enzyme | A protein that acts as a catalyst, speeding the rate at which a biochemical reaction proceeds but not altering the direction or nature of the reaction. |
| DNA sequence | The relative order of base pairs, whether in a fragment of DNA, a gene, a chromosome, or an entire genome. See base sequence. |
| 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). |
| Endonuclease | An enzyme that cleaves its nucleic acid substrate at internal sites in the nucleotide or base sequence. See also restriction enzyme. |