(pronounced /maɪˈoʊsɨs/ ( listen)) is a special type of cell division necessary for sexual reproduction. The cells produced by meiosis are gametes or spores. The animals' gametes arecalled sperm and egg cells.
Whilst the process of meiosis bears a number of similarities with the 'life-cycle' cell division process of mitosis, it differs in two important respects:
the chromosomes inmeiosis undergo a recombination which shuffles the genes producing a different genetic combination in each gamete, compared with the co-existence of each of the two separate pairs of each chromosome(one received from each parent) in each cell which results from mitosis.
the outcome of meiosis is four (genetically unique) haploid cells, compared with the two (genetically identical) diploid cellsproduced from mitosis.
is the scientific term for nuclear cell division, where the nucleus of the cell divides, resulting in two sets of identical chromosomes. Mitosis is accompanied bycytokinesis in which the end result is two completely separate cells called daughter cells. There are four phases of mitosis: prophase, metaphase, anaphase and telophase.
The first phase of mitosisis prophase. In this phase the chromosomes which are normally spread throughout the nucleus begin to condense into a tight ball. The DNA molecules of the chromosomes begin to interact with enzymes andproteins that assist in the replication of the genes. The compact coiling of the chromosomes at this stage of mitosis is called mitotic chromosomes. Nearing the end of prophase, the materialenclosing the nucleus and the cytoskeleton disappears. The cytoskeleton is transformed into what is called a spindle apparatus which works to pull the duplicated chromosomes apart during the anaphase.
Thesecond phase of mitosis is metaphase. In this phase the chromosomes of the dividing cell begin to line up and are coordinated with the spindle apparatus. The soon to be divided chromosomes are...