Definitions for macronucleusˌmæk roʊˈnu kli əs, -ˈnyu-

This page provides all possible meanings and translations of the word macronucleus


  1. macronucleus(Noun)

    The larger the two nuclei present in ciliate protozoans; it controls the nonreproductive functions of the cell.


  1. Macronucleus

    A macronucleus 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.

U.S. National Library of Medicine

  1. Macronucleus

    The larger of two types of nuclei in ciliate protozoans. It is the transcriptionally active nucleus of the vegetative cells as distinguished from the smaller transcriptionally inert GERMLINE MICRONUCLEUS.


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