Difference Between Meiosis I vs. Meiosis II

Main Difference

Meiosis is the type of cell division, which happens only once in the lifetime of a eukaryote. This process is essential for the eukaryotic organisms as in this gametes, or sex cells are formed after the genetic material is mixed or rearranged. In the process of meiosis, the number of chromosomes in the parent cell are reduced to half, and four gamete cells are produced. Meiosis produces the eggs and sperm cells, which are used by the organism for sexual reproduction. The whole process of meiosis can be mainly divided into two smaller processes, Meiosis I and Meiosis II. In Meiosis I, the diploid parent cell forms haploid daughter cells, and the number of chromosomes in this process are reduced to half, whereas in Meiosis II the two haploid parent cells produce four haploid daughter cells, and the number of chromosomes remains the same.

Comparison Chart

BasisMeiosis IMeiosis II
Number of chromosomesIn meiosis I, the number of chromosomes are reduced to half.In meiosis II, the number of chromosomes remains the same
ProductionHaploid daughter cells are formed from the diploid parent cellHaploid daughter cells are formed from the haploid parent cell.
Complicated and Longer processYesNo
Crossing over of chromosomesYesNo

What is Meiosis I?

It is the process of cell division in which the number of chromosomes is reduced to half, and the haploid daughter cells are formed from the diploid parent cell. This cell division process commences with one cell and ends with two cell where the number of chromosomes also reduced to the half. As compare to the meiosis II, it is a more complicated and longer type of cell division. In this process of cell division, the homologous chromosomes underwent the separation, resulting in the formation of two gametes. Meiosis I starts with the shrinkage of the chromosome in the nucleus of the only diploid cell. In meiosis I, recombination or mixing of chromosome pairs happens which end as reducing the number of chromosomes, whereas such kind of process is absent in the meiosis II. Meiosis I and Meiosis II undergo the same five stages; prophase, prometaphase, metaphase, anaphase, and telophase. The main difference comes in the prophase of meiosis I, which is longer and more complicated than it is in the process of meiosis II.

What is Meiosis II?

It is the process of cell division in which the number of chromosomes remains the same, and four haploid daughter cells are formed from the haploid parent cell. It is simpler, and a shorter process as compared to the meiosis I and in this the two chromatids of replicated chromosome are separated. Meiosis II resembles the process of mitosis, which is an asexual process of cell division that happens in every of the organism. Apart from the close resemblance with the process of mitosis, the difference it possesses is the presence of two parent cells instead of the only one parent cell. The process of meiosis II, which ends up with four daughter cells is the short duration process in which the crossing over of chromosomes doesn’t happen and furthermore, the sister chromatids are separated in this process.

Key Differences

  1. In meiosis I the number of chromosomes are reduced to half, and the haploid daughter cells are formed from the diploid parent cell, whereas in meiosis II number of chromosomes remain the same, and four haploid daughter cells are formed from the haploid parent cell.
  2. As compared to the meiosis II, meiosis I is a more complicated and longer type of cell division.
  3. Meiosis II closely resembles the process of mitosis.
  4. The crossing over of chromosomes happens in the meiosis I, although it is absent in the meiosis II.

Comparison Video

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