Macronucleus

A macronucleus (formerly also meganucleus) is the larger type of nucleus in ciliates. Macronuclei are polyploid and undergo direct division without mitosis. It controls the non-reproductive cell functions, the everyday tasks, such as metabolism. During conjugation, the macronucleus disintegrates, and a new macronucleus is formed by karyogamy of the micronuclei. The macronucleus contains hundreds of chromosomes, each present in many copies. The macronucleus lacks a mechanism to precisely partition this complex genome equally during nuclear division; thus how the cell manages to maintain a balanced genome after generations of divisions is a mystery.

See also

• Micronucleus

This protist-related article is a stub. You can help Wikipedia by expanding it.v · Categories: Organelles Protist stubs Wikimedia Foundation. 2010. Игры ⚽ Поможем решить контрольную работу Codnor Money Game Look at other dictionaries: macronucléus — ● macronucléus nom masculin Le plus gros noyau des protozoaires ciliés, par opposition avec le plus petit, ou micronucléus. macronucleus n. m. BIOL élément constitutif, avec le micronucleus, du noyau des infusoires …   Encyclopédie Universelle macronucleus — macronucleus. См. макронуклеус. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь. macronucleus — [mak΄rō no͞o′klē əs] n. the larger of two types of nuclei present in the cells of ciliated protozoans macronuclear adj …   English World dictionary macronucleus — The larger nucleus (or sometimes nuclei) in ciliate protozoans. Derived from the micronucleus by a process of DNA polytenisation. The DNA in the macronucleus is actively transcribed. The macronucleus degenerates before conjugation …   Dictionary of molecular biology macronucleus — macronuclear, adj. /mak roh nooh klee euhs, nyooh /, n. Biol. the larger of the two types of nuclei occurring in ciliate protozoans, having a multiple set of chromosomes and functioning in cell metabolism and protein synthesis. Cf. micronucleus.… …   Universalium macronucleus — noun The larger the two nuclei present in ciliate protozoans; it controls the nonreproductive functions of the cell. These binucleated forms have one macronucleus functional and another sexual micronucleus which is not functional in the ordinary… …   Wiktionary macronucleus-destined sequences — macronucleus destined sequences. См. предназначенные для макронуклеуса последовательности. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь. macronucleus — noun Etymology: New Latin Date: 1892 a relatively large densely staining nucleus of most ciliate protozoans that is derived from micronuclei and controls various nonreproductive functions • macronuclear adjective …   New Collegiate Dictionary macronucleus — (mak ro nu kle us) The larger of the two nuclei in ciliate protozoa. It is normally polyploid and directs the routine activities of the cell …   Dictionary of microbiology macronucleus — 1. A nucleus that occupies a relatively large portion of the cell, or the larger nucleus where two or more are present in a cell. SYN: meganucleus. 2. The larger of the two nuclei in ciliates, which governs vegetative metabolic functio …   Medical dictionary 18+ © Academic, 2000-2024 Contact us: Technical Support, Advertising Dictionaries export, created on PHP, Joomla, Drupal, WordPress, MODx. Mark and share Search through all dictionaries Translate… Search Internet Share the article and excerpts Direct link … Do a right-click on the link above and select “Copy Link”