mitosis

[ mahy-toh-sis ]

noun

, Cell Biology.

1. the usual method of cell division, characterized typically by the resolving of the chromatin of the nucleus into a threadlike form, which condenses into chromosomes, each of which separates longitudinally into two parts, one part of each chromosome being retained in each of two new cells resulting from the original cell. Compare meiosis ( def 1 ).

mitosis

/ mɪ-; maɪˈtəʊsɪs; mɪ-; maɪˈtɒtɪk /

noun

1. See meiosis, telophase, anaphase, metaphase, prophase
   a method of cell division, in which the nucleus divides into daughter nuclei, each containing the same number of chromosomes as the parent nucleus Compare prophase metaphase anaphase telophase meiosis

mitosis

/ mī-tō′sĭs /

1. 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.
2. Compare meiosis

mitosis

1. Division of a single cell into two identical “daughter” cells. Each daughter cell has an identical number of chromosomes as the parent cell. Mitosis begins when the DNA in the parent cell replicates itself; it ends with two cells having the same genes ( see genetics ). Most cells in the human body, and all single-celled organisms, reproduce through mitosis. ( Compare meiosis .)

Derived Forms

• miˈtotically, adverb
• mitotic, adjective

Other Words From

• mi·tot·ic [mahy-, tot, -ik], adjective
• mi·toti·cal·ly adverb
• inter·mi·totic adjective

Word History and Origins

Origin of mitosis¹

First recorded in 1885–90; from Greek mít(os) “thread” + -osis

Word History and Origins

Origin of mitosis¹

C19: from New Latin, from Greek mitos thread

A 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.

Example Sentences

In this way Klingemann created Mitosis, meaning the moment when the embryo begins to form.

From Nautilus

Each of these divides again by mitosis (the chromosomes splitting lengthwise), the half or haploid number remaining.

From Project Gutenberg

Since the atomic wars, the increased radioactivity of the earth undoubtedly stimulates mitosis of the malignant cells.

From Project Gutenberg

This increase is therefore reached at an earlier period in the larger wound since the process of mitosis is more rapid here.

From Project Gutenberg

As noted, in fission the meganucleus divides by direct constriction; each micronucleus by a mode of mitosis.

From Project Gutenberg

Whatever be the number of chromosomes that enter a new nucleus as it forms, the same number issues from it in mitosis.

From Project Gutenberg