Mitosis and Meiosis

Cell division and reproduction can occur in two ways - mitosis and meiosis.

Mitosis is a process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical daughter cells.

Meiosis, on the other hand, is a division of a germ cell involving two fissions of the nucleus and giving rise to four gametes, or sex cells, each possessing half the number of chromosomes of the original cell.

Mitosis is used by single celled organisms to reproduce; it is also used for the organic growth of tissues, fibers, and membranes. Meiosis is useful for sexual reproduction of organisms. The male and female sex cells, e.g. the spermatozoa and egg, fuse to create a new, singular biological organism.

Process Differences
Different Stages of Mitosis and Meiosis
Differences in Purpose

Mitosis is a method of reproduction for single celled organisms that reproduceasexually. An identical version of the organism is created through splitting of the cell in two. Meiosis may result in millions of spermazoa and egg cells with unique genetic patterns. The mating of the two cells formed by meiosis results in a unique genetic offspring of the same species. Meiosis is a major factor in evolution, natural selection, and biodiversity. The processes of cellular division shown in mitosis and meiosis are present in all manner of life forms including humans, animals, plants, fungi, and single celled organisms and species. Essentially any cell based organism of which all organic life is based will exhibit some form of mitosis and meiosis for growth and reproduction of the individual and species.

The different phases of meiosis are: Prophase, Metaphase, Anaphase and Telophase.

Both Meiosis and Mitosis are found in complex organisms which reproduce sexually. Mitosis may be used for human growth, the replenishment of depleted organs and tissues, healing, and sustenance of the body. Identical versions of cells can be created to form tissues through Mitosis. Meiosis is a special process reserved for the creation of the egg and sperm cells. The same patterns may be found in many species of plant and animal cell reproduction.

Significance

Meiosis	Mitosis
Definition	A type of cellular reproduction in which the number of chromosomes are reduced by half through the separation of homologous chromosomes, producing two haploid cells.	A process of asexual reproductionin which the cell divides in two producing a replica, with an equal number of chromosomes in each resulting diploid cell.
Function	sexual reproduction	Cellular Reproduction & general growth and repair of the body
Type of Reproduction	Sexual	Asexual
Occurs in	Humans, animals, plants, fungi	all organisms
Genetically	different	identical
Crossing Over	Yes, mixing of chromosomes can occur.	No, crossing over cannot occur.
Pairing of Homologs	Yes	No
Number of Divisions	2	1
Number of Daughter Cells produced	4 haploid cells	2 diploid cells
Chromosome Number	Reduced by half	Remains the same
Steps	The steps of meiosis are Interphase, Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II and Telophase II.	The steps of mitosis are Interphase, Prophase, Metaphase, Anaphase, Telophase and Cytokinesis
Karyokinesis	Occurs in Interphase I	Occurs in Interphase
Cytokinesis	Occurs in Telophase I & Telophase II	Occurs in Telophase
Centromeres Split	The centromeres do not separate during anaphase I, but during anaphase II	The centromeres split during Anaphase
Creates	Sex cells only: Female egg cells or Male sperm cells	Makes everything other than sex cells

The importance of mitosis is the maintenance of the chromosomal set; each cell formed receives chromosomes that are alike in composition and equal in number to the chromosomes of the parent cell.