Two cell divisions mitosis or meiosis

2 answers:

8 0

Cell division is the process by which a parent cell divides into two or more daughter cells.[1]Cell division usually occurs as part of a larger cell cycle. In eukaryotes, there are two distinct types of cell division: a vegetative division, whereby each daughter cell is genetically identical to the parent cell (mitosis),[2] and a reproductive cell division, whereby the number of chromosomes in the daughter cells is reduced by half to produce haploid gametes(meiosis). Meiosis results in four haploid daughter cells by undergoing one round of DNA replication followed by two divisions. Homologous chromosomes are separated in the first division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Both are believed to be present in the last eukaryotic common ancestor.

Prokaryotes (bacteria) undergo a vegetative cell division known as binary fission, where their genetic material is segregated equally into two daughter cells. All cell divisions, regardless of organism, are preceded by a single round of DNA replication.

For simple unicellular microorganisms such as the amoeba, one cell division is equivalent to reproduction – an entire new organism is created. On a larger scale, mitotic cell division can create progeny from multicellular organisms, such as plants that grow from cuttings. Mitotic cell division enables sexually reproducing organisms to develop from the one-celled zygote, which itself was produced by meiotic cell division from gametes. After growth, cell division by mitosis allows for continual construction and repair of the organism.[3] The human body experiences about 10 quadrillion cell divisions in a lifetime.[4]

The primary concern of cell division is the maintenance of the original cell's genome. Before division can occur, the genomic information that is stored in chromosomes must be replicated, and the duplicated genome must be separated cleanly between cells.[5] A great deal of cellular infrastructure is involved in keeping genomic information consistent between generations.

IrinaK [193]3 years ago

5 0

mitosis is the answer

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1) DNA is wrapped around histone proteins to form chromatin

2) The genes are the functional units, the segments between them are used for regulation

3) The genetic code is the language used, gene expression is how the cell uses the information, the activity of the genes.

Explanation:

1) DNA forms a DNA/protein complex called chromatin. It does this by wrapping around histone proteins. These histone proteins are usually present in the form of a nucleosome, which is a unit containing 2 copies of 4 histones (H2A, H2B, H3 and H4). The chromatin fibre at its most compact forms tightly coiled structures called chromosomes. These structures are only present during cell division. When the cell is in interphase (i.e. not dividing), the chromatin is not as tightly condensed, and instead the chromatin is more relaxed to allow the genes within to be expressed.

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<span>Meiosis is the prosess in which cells split</span><span />

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