macronucleus

[ mak-roh-noo-klee-uhs, -nyoo- ]

noun

, Biology.

1. the larger of the two types of nuclei nucleus occurring in ciliate protozoans, having a multiple set of chromosomes and functioning in cell metabolism and protein synthesis.

macronucleus

/ ˌmækrəʊˈnjuːklɪəs /

noun

1. the larger of the two nuclei in ciliated protozoans Compare micronucleus

Other Words From

• macro·nucle·ar adjective

Word History and Origins

Origin of macronucleus¹

From New Latin, dating back to 1890–95; macro-, nucleus

Example Sentences

There are three different sets of self-duplicating nuclei, with the DNA in each set serving different purposes: a large macronucleus, governing the events in regeneration after injury, a set of eight or more micronuclei containing the parts of the genome needed for reproduction, and great numbers of tiny nuclei from which the cilia arise.

From Literature

The clear spot to the right is the macronucleus, and the blobs are probably storage granules of some sort.

From Scientific American

In the centre lies a sizeable macronucleus, which stores the chromatin used for making the various genome products.

From Scientific American

The details of ciliate sex, and the behavior of the micronucleus and the macronucleus, differ slightly from one species to the next; my description is taken from the aforementioned Margulis and Schwartz, and also from Jönsson, F., Postberg, J. and Lipps, H. J. 2009.

From New York Times

The macronucleus is made from the micronucleus, but it is not at all the same in content.

From New York Times