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Cell division is the process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle. There are two different types of eukaryotic cell division. Nutritional division, in which each daughter cell is genetically identical to the mother cell (mitosis), and germ cell division, in which the number of chromosomes in the daughter cell is reduced by half to produce haploid gametes (meiosis).
Mitosis:
In cell biology, mitosis is part of the cell cycle in which a replicated chromosome is separated into two new nuclei. Cell division produces genetically identical cells in which the total number of chromosomes is conserved. Therefore, mitosis is also known as the division of equations. The various stages of mitosis come together to define the mitotic (M) phase of the animal cell cycle, that is, the division of a mother cell into two genetically identical daughter cells.
Mitosis occurs only in eukaryotic cells. Prokaryotic cells lacking a nucleus divide through another process called binary fission [citation needed]. Mitosis varies from organism to organism. Most animal cells undergo a shape change known as mitotic roundness because they take a nearly spherical morphology at the onset of mitosis. Most human cells are formed by mitotic cell division. A key exception is gametes (sperm and egg cells) formed by meiosis.
Significance of mitosis:
The “function” or importance of mitosis is based on the maintenance of chromosomal sets. Each cell formed receives a chromosome that is similar in composition and number to the chromosome of the parent cell. Mitosis occurs in the following situations:
Development and growth:
The number of cells in an organism is increased by mitosis. This is the basis for developing multicellular bodies from a single cell. It is a zygote and the basis for the growth of multicellular bodies.
Cell replacement:
Similar to the exact copy of the cell to be replaced, new cells are formed by mitosis. Similarly, red blood cells have a short lifespan (only about 4 months), and mitosis forms new RBCs.
Regeneration:
Some organisms can regenerate parts of their body. In such cases, the production of new cells is achieved by mitosis. For example, starfish regenerate the arm lost due to mitosis.
Meiosis:
Meiosis is a special type of cell division of gametes in sexual reproduction and is used to produce gametes such as sperm and egg cells. This involves two divisions, eventually resulting in four cells with only one copy of each chromosome (haploid). In addition, prior to division, genetic material from the paternal and maternal copies of each chromosome is mated to create a new coding combination on each chromosome. Then, during fertilisation, the haploid cells produced by meiosis by males and females fuse to recreate zygotes, cells with two copies of each chromosome.
Meiosis produces a haploid gamete (ovule or sperm) containing a set of 23 chromosomes. When the two gametes (egg and sperm) fuse, the resulting zygote becomes diploid again, and the mother and father each contribute to 23 chromosomes. This same pattern occurs in all organisms that use meiosis, not the same number of chromosomes.
Significance of meiosis:
Meiosis is an important event in the eukaryotic sexual cycle. This is the stage of the life cycle in which cells give birth to haploid cells (gametes), and each cell has half the chromosomes of its parent cell. Normally, two such haploid gametes originating from different individual organisms fuse through the process of fertilization to complete the sexual cycle.
Meiosis is ubiquitous in eukaryotes. It is found in both unicellular organisms such as yeast and multicellular organisms such as humans. New combinations of DNA that occur during meiosis are important causes of genetic variation along with mutations, leading to new combinations of alleles that may be beneficial.
Conclusion:
In mitosis and meiosis, cells divide to form new cells. This makes them both important processes for the presence of sexually reproducing organisms. Meiosis gives rise to the cells required for sexual reproduction, and mitosis replicates the non-sexual cells required for growth and development. Together they form a cell base for healthy growth and sexual reproduction.
