mitosis
Americannoun
noun
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012-
The process in cell division in eukaryotes in which the nucleus divides to produce two new nuclei, each having the same number and type of chromosomes as the original. Prior to mitosis, each chromosome is replicated to form two identical strands (called chromatids). As mitosis begins, the chromosomes line up along the center of the cell by attaching to the fibers of the cell spindle. The pairs of chromatids then separate, each strand of a pair moving to an opposite end of the cell. When a new membrane forms around each of the two groups of chromosomes, division of the nucleus is complete. The four main phases of mitosis are prophase, metaphase, anaphase, and telophase.
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Compare meiosis
Closer Look
Mitosis is the process by which the nucleus divides in eukaryotic organisms, producing two new nuclei that are genetically identical to the nucleus of the parent cell. diamf3 It occurs in cell division carried on by human somatic cells—the cells used for the maintenance and growth of the body. These cells have two paired sets of 23 chromosomes, or 46 chromosomes in total. (Cells with two sets of chromosomes are called diploid.) Before cell division occurs, the genetic material in each chromosome is duplicated as part of the normal functioning of the cell. Each chromosome then consists of two chromatids, identical strands of DNA. When a cell undergoes mitosis, the chromosomes condense into 46 compact bodies. The chromatids then separate, and one chromatid from each of the 46 chromosomes moves to each side of the cell as it prepares to divide. The chromatids form the chromosomes of the daughter cells, so that each new cell has 46 chromosomes, (two complete sets of 23) just like the parent cell. While both mitosis and meiosis refer properly to types of nuclear division, they are often used as shorthand to refer to the entire processes of cell division themselves. When mitosis and meiosis are used to refer specifically to nuclear division, they are often contrasted with cytokinesis, the division of the cytoplasm.
Other Word Forms
- intermitotic adjective
- mitotic adjective
- mitotically adverb
Etymology
Origin of mitosis
First recorded in 1885–90; from Greek mít(os) “thread” + -osis
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Many of these loops allow genes to interact with distant regulatory regions -- sometimes millions of base pairs apart -- while others form during mitosis to pack chromosomes tightly.
From Science Daily
The two differ, however, in how they carry out many physiological processes, including the most common type of cell division -- mitosis.
From Science Daily
In this study, Underwood and his team established a system, in which they replace the meiosis by mitosis, a simple cell division, in the most popular vegetable crop plant, the cultivated tomato.
From Science Daily
This reproduction process is referred to as cell division or mitosis.
From Science Daily
"In the stressed environment in the study, APC activation occurred before mitosis, when it's usually been known to activate only during mitosis," says Regot.
From Science Daily
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.