| punctuation codon | <molecular biology> The three codons, UAA known as ochre, UAG as amber and UGA as opal, that do not code for an amino acid but act as signals for the termination of protein synthesis. They are not represented by any tRNA and termination is catalysed by protein release factors. There are two release factors in E. Coli, RF1 recognises UAA and UAG, RF2 recognises UAA and UGA. Eukaryotes have a single GTP requiring factor, eRF. See: ochre suppressor, amber suppressor. (13 Jan 1998) |
|---|---|
| start codon | The codon 5' AUG in mRNA, at which polypeptide synthesis is started. It is recognised by formylmethionyl tRNA in bacteria and by methionyl tRNA in eukaryotes. (18 Nov 1997) |
| stop codon | <molecular biology> The three codons, UAA known as ochre, UAG as amber and UGA as opal, that do not code for an amino acid but act as signals for the termination of protein synthesis. They are not represented by any tRNA and termination is catalysed by protein release factors. There are two release factors in E. Coli, RF1 recognises UAA and UAG, RF2 recognises UAA and UGA. Eukaryotes have a single GTP requiring factor, eRF. See: ochre suppressor, amber suppressor. (13 Jan 1998) |
| nonsense codon | <molecular biology> The three codons, UAA (known as ochre), UAG (amber) and UGA (opal), that do not code for an amino acid but act as signals for the termination of protein synthesis. Any mutation that causes a base change which produces a nonsense codon results in premature termination of protein synthesis and probably a nonfunctional or nonsense protein. (13 Nov 1997) |
| initiating codon | The trinucleotide AUG (or sometimes GUG) that codes for the first amino acid in protein sequences, formylmethionine; the latter is often removed post-transcriptionally. Synonym: start codon. (05 Mar 2000) |
| initiation codon | The codon 5' AUG in mRNA, at which polypeptide synthesis is started. It is recognised by formylmethionyl tRNA in bacteria and by methionyl tRNA in eukaryotes. (18 Nov 1997) |
| ochre codon | The codon UAA, one of the three that causes termination of protein synthesis. The most frequent termination codon in E. Coli genes. (18 Nov 1997) |
| opal codon | <molecular biology> The codon UGA, one of the three that causes termination of protein synthesis. (18 Nov 1997) |
| termination codon | <molecular biology> The three codons, UAA known as ochre, UAG as amber and UGA as opal, that do not code for an amino acid but act as signals for the termination of protein synthesis. They are not represented by any tRNA and termination is catalysed by protein release factors. There are two release factors in E. Coli, RF1 recognises UAA and UAG, RF2 recognises UAA and UGA. Eukaryotes have a single GTP requiring factor, eRF. See: ochre suppressor, amber suppressor. (13 Jan 1998) |
| umber codon | The termination codon UGA. Synonym: opal codon. (05 Mar 2000) |
| abortion, multiple | Couples who have had 2 or more miscarriages (spontaneous abortions) have about a 5% chance that one member of the couple is carrying a chromsome translocation responsible for the miscarriages. (12 Dec 1998) |
| advanced multiple-beam equalization radiography | A variant of scanning equalization radiography using several X-ray beams. (05 Mar 2000) |
| amyloidosis of multiple myeloma | Foci of amyloidosis in mesenchymal tissues of some persons with multiple myeloma; no direct relation between amyloid and Bence Jones protein is conclusively known. (05 Mar 2000) |
| cancer, multiple myeloma | A bone marrow cancer involving a type of white blood cell called a plasma (or myeloma) cell. The tumour cells can form a single collection (a plasmacytoma) or many tumours (multiple myeloma). Plasma cells are part of the immune system and make antibodies. Because patients have an excess of identical plasma cells, they have too much of one type of antibody. As myeloma cells increase in number, they damage and weaken the bones, causing pain and often fractures. When bones are damaged, calcium is released into the blood leading to hypercalcaemia (excess calcium in the blood) and that causes loss of appetite, nausea, thirst, fatigue, muscle weakness, restlessness, and confusion. Myeloma cells prevent the bone marrow from forming normal plasma cells and other white blood cells important to the immune system so patients may not be able to fight infections. The cancer cells can also prevent the growth of new red blood cells, causing anaemia. Excess antibody proteins and calcium may prevent the kidneys from filtering and cleaning the blood properly Cancer, non-Hodgkin's lymphoma: A lymphoma is a cancer that develops in the lymphatic system. The most common symptom of non-Hodgkin's lymphomas is a painless swelling in the lymph nodes in the neck, underarm, or groin. Non-Hodgkin's lymphomas are diagnosed with a biopsy of an enlarged lymph node. Follow-up examinations are important after lymphoma treatment. Most relapses occur in the first 2 years after therapy. (12 Dec 1998) |
| chromosomes in multiple miscarriages | Couples who have had more than one miscarriage (spontaneous abortion) have about a 5% chance that one member of the couple is carrying a chromsome translocation responsible for the miscarriages. (12 Dec 1998) |