The Differences Between Mitosis and Meiosis

Mitosis and meiosis are the two tricky processes of cell division that send every biology student running to the textbooks. Students often confuse the functions of one for the other, are unclear as to what function each serves, or are unclear abut where each differs from the other.

The first point to understand is where mitosis and meiosis take place. This is one of the first major differences between the two. Mitosis takes place within somatic cells (cells that make up the body), while meiosis takes place within gamete cells (sex cells). As such, meiosis produces more gamete cells, and mitosis produces somatic cells. Mitosis is the process which is responsible for replacing dead or wounded skin cells. Mitosis divides a single somatic cell into two daughter cells, while gametes are produced in fours; more specifically, one single cell produces four daughter cells.

The type of cell that each process occurs in also affects how many chromosomes that each mother cell has. Somatic cells can have either a haploid or diploid of chromosomes. The number of chromosomes in the mother cell are duplicated in the new daughter cells, so both mother cell and daughter cell have an equal number of chromosomes. Meiosis' gamete cells are found only with a diploid of chromosomes. The mother cell will then divide leaving its four daughter cells with a haploid of chromosomes. This is because the chromosomes of a female and male sex cell merge when the female egg is fertilized and thus the new cell (formed through fertilization) will have a diploid of chromosomes from which to build upon as the new organism develops.

DNA duplication is also confused as occurring in both Mitosis and Meiosis. In one regard, this assumption is correct. However, this correctness requires that a person specify at which stage of meiosis DNA duplication occurs. DNA duplication occurs during S phase of Mitosis as well as S phase of Meiosis I. Meiosis II does not see the S phase and as such does not see DNA duplication.

Prophase one also sees a difference between functions. Meiosis pairs all homologous chromosomes during prophase 1; however, Mitosis leaves this part our of its process. It also leaves out cross over, the event at which chromatids break off of their chromosome and reattach to a new chromosome creating variety in chromosomal make up. Mitosis' function would explain why cross over wouldn't be needed. As I mentioned, Mitosis is responsible for creating new cells that will replace dead or wounded cells. There is no need for genetic differences between these cells. However, a gamete is responsible for contributing to the traits a specific individual has. If cross over did not occur the new gametes would be identical to their mother cell in every way. The organism created from the fertilization would also be lacking in a great deal of varied traits, it would be a copy of its parents while now people have variety in their traits creating originality. Yes, we resemble our parents, but we don't look exactly alike, we have variations that make us unique.

Lastly, Meiosis offers an additional anaphase called anaphase II in which the centromeres split aiding in the split of the cell. The additional anaphase also allows time for the split of four cells instead of two. During Mitosis this happens during anaphase (I), so there is no anaphase II.

While Mitosis and Meiosis may be confusing concepts, knowing the differences between the two can greatly help in overall understanding and test taking on the subject matter.