The growth and reproduction of cells are made possible through the process of cell division.
In eukaryotic cells, the division of cell occurs in two ways: mitosis and meiosis. They are called nuclear division. They share the same characteristics but differ in some ways. (1, 2)
Image 1: Cell division using the process of mitosis.
Picture Source: cloudfront.net
The process of mitosis duplicates and divides two cells equally. The cellular division follows a path of events also known as the cell cycle. The cell cycle in mitosis is possible if there are growth factors and other signs that may indicate that a new cell needs to be produced.
Some cells in the body require the process of mitosis in order to replicate. They are called somatic cells. Examples are:
- Fat cells
- Skin cells
- Blood cells
- Cells in the body that are not categorized as sex cells. (1, 2, and 3)
Importance of mitosis
The process of mitosis in somatic cells is essential as, through it, dead and damaged cells will be replaced.
Image 2: Cellular division using the process of meiosis.
Picture Source: wikimedia.org
It is the process by which the sex cells (gametes) are produced in organisms that require sexual reproduction. Both male and female gonads produce gametes/sex cells. The chromosomes they contain is only half of the parent cell.
Half the number of chromosomes from the father cell and half the number of chromosomes from the mother cell. The meiotic cell cycle will result in four daughter cells that are distinct in genetic components. (3, 4, and 5)
What are the similarities between mitosis and meiosis?
- They are both diploid parent cells.
- They both have a growth period called interphase.
- They both involve various phases such as the prophase, anaphase, metaphase, and telophase.
- Both of the sister chromatids line up along the metaphase plate.
- They both involve the separation of sister chromatids and the formation of daughter chromosomes.
- They both end up with cytoplasm division leading to the production of individual cells.
- They both end with cytokinesis. (2, 4, 5, and 6)
Image 3: A comparison image between mitosis and meiosis.
Picture Source: teacherspayteachers.com
Image 4: A Venn diagram showing the similarities and differences between mitosis and meiosis.
Picture Source: ytimg.com
Image 5: The processes involved in mitosis and meiosis.
Picture Source: quoracdn.net
What are the differences between Mitosis and Meiosis?
In mitosis, the cell divides only once. The cytoplasm divides at the end of the telophase. On the other hand, meiosis undergoes division twice. It takes place at the end of telophase I and telophase II.
Number of daughter cells
Cell division in mitosis results in the production of two daughter cells. Each cell is diploid, which means that they contain exact chromosomes. In meiosis, the resulting product is four daughter cells and each cell is diploid. Each contains only half of the parent cell’s chromosomes. (6, 7)
In mitosis, the daughter cells produced are the same in genetic compositions primarily because there is no crossing over or recombination occurred.
In meiosis, the end products have different gene combinations. Recombination of genes is made possible because of random separation of homologous chromosomes into various cells. The genes transfer between homologous chromosomes.
Mitosis does not have a tetrad formation. On the other hand, tetrad formation occurs in meiosis. Tetrads are formed in prophase I. the tetrad has four chromatids.
Alignment of chromosomes in metaphase
In mitosis, the sister chromatids form a line at the metaphase plate. On the other hand, in meiosis, tetrads form a line at the metaphase plate which typically occurs in metaphase I. (8, 9, and 10)
Separation of chromosomes
In mitosis, the separation of sister chromatids takes place during anaphase. They began migrating centromere first towards the cell’s opposite poles. The sister chromatids become the daughter chromosomes which becomes a full chromosome.
During meiosis, the homologous chromosomes travel to the cell’s opposite poles during anaphase I. in anaphase I, there is no separation of sister chromatids. (1, 3)
For detailed information about the differences between mitosis and meiosis refer to the table below.
|Point of comparison||Mitosis||Meiosis|
|Number of cell division||One cell division||Two successive cell divisions|
|Number of daughter cells||Two daughter cells||Four daughter cells|
|Resulting daughter cells||Diploid (the number of chromosomes is the same as the parent cell)||Haploid (contains half the number of chromosomes of the parent cell)|
|Characteristic of daughter cells||The daughter cells are identical in genetic structures.||The four daughter cells are different in genetic components.|
|Where it occurs||It takes place in almost all organisms with the exception of viruses.||It only takes place in animals, fungi, and plants (4, 5)|
|Length of prophase||Short||Long|
|Recombination/crossing over||No||Yes (recombination/crossing over takes place in prophase I)|
|Pairing of homologs||No||Yes|
|Nature of mother cells||Mother cells can be haploid or diploid.||The mother cells are always diploid.|
|Pairing of chromosomes||Does not occur||Pairing of chromosomes happens during prophase I and continues up to metaphase I.|
|Where it takes place||Somatic cells||Germ cells|
|Functions||It plays a vital role in cellular reproduction and growth.||Its primary function is for genetic diversity through sexual reproduction.|
|It facilitates repair of the body.||It takes an important role in gamete formation and maintenance of the number of chromosomes. (1, 6, and 9)|
|It is important for the body’s healing and repair. (2, 4, and 7)|
|Discovered by||Walther Flemming||Oscar Hertwig|
Mitosis and meiosis are both cellular division processes. They have similar and distinct functions and characteristics. Mitosis primarily occurs in somatic cells and their primary function is to facilitate growth, repair, and replacement of old and damaged cells. It is extremely important in producing more cells, especially in the early developmental stage.
Mitosis is also important in the regeneration of damaged and lost cells. On the other hand, meiosis only takes place in sex cells of living organisms so as to maintain the required number of chromosomes of the offspring.
It also helps maintain genetic diversity wherein the process of natural selection takes place. Without meiosis, the perpetuation of species will not take place. (3, 6, 8, and 9)