Similarities and Differences in Mitosis and Meiosis - Essay Example

Mitosis comprises of standard steps of Interphase, Prophase, Prometaphase, Anaphase and Telophase. Interphase is the process where cell prepares material for cell division. In this phase chromosomes are unseen, but chromatin granules are seen clearly.(Lehninger, 2008) In the Prophase in mitosis, four chromatids combine to form a pair of chromosomes which are joined by a centromere. Comparatively in Meiosis Prophase I, four chromosomes instead of chromatids combine to form two tetrads. The chromosomes in the tetrad cross over each other, allowing them to exchange genetic material.

In the Metaphase in Mitosis, the two chromosomes line up in the center and split up into four chromatids which move to both of the poles. In Parallel, in meiosis, the two tetrads line up in the center and split up into four chromosomes which go to both poles. In the Telophase, all the material that has migrated to the poles gets enclosed by the nuclear envelope in Mitosis as well as meiosis. Mitosis is completed at this stage. Meiosis then proceeds to Meiosis II which is identical to mitosis.

DNA replication is skipped in interphase and the cells proceed to divide exactly by the mechanism of mitosis.Thus mitosis involves a single nuclear division which gives rise to two identical daughter nuclei. Meiosis on the other hand involves two successive nuclear divisions and hence one diploid cell gives rise to four haploid cells. Consequently for mitosis to occur, the mother cell can be either haploid or diploid. However for meiosis to occur the mother cell has to be necessary diploid so that the chromosome number can be halved.

Mitosis generally occurs in all somatic cells of the body whereas meiosis occurs only in the sex cells in the body. The number of chromosomes per nucleus remains the same after division i.e n remains n and same applies for 2n. The meiotic products contain a haploid (n) number of chromosomes, in contrast to the 2n mother cell. Mitosis is preceded by an S-phase in which the amount of DNA is duplicated. Only meiosis I is preceded by an S-phase. (Radboud University, 2003) Meiosis II proceeds without a pre S phase.

Homologous chromosomes remain independent in mitosis. On the other hand complete