Meiosis I vs. Meiosis II

The process of meiosis becomes critical in the formation of the reproductive cells, and therefore several important steps become involved. The two getting discussed here have their key differences. The term Meiosis I gets defined as the first main division of the nucleus of the eukaryotic cell during the process of meiosis and has the following stages involved; prophase I, metaphase I, anaphase I and telophase I. The term Meiosis II gets defined as the last main division of the nucleus of the eukaryotic cell during the process of meiosis and has the following stages involved; prophase II, metaphase II, anaphase II and telophase II.

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Meiosis I vs. Meiosis II

Comparison Chart

Basis of DistinctionMeiosis IMeiosis II
Definition The first main division of the nucleus of the eukaryotic cell during the process of meiosis.The last main division of the nucleus of the eukaryotic cell during the process of meiosis
StepsProphase I, metaphase I, anaphase I and telophase I.Prophase II, metaphase II, anaphase II and telophase II.
TaskForming the two haploid cells from one diploid cell present.Splitting the sister chromatids present within the haploid cells produced during
NatureHeterotypic divisionHomotypic division
WorkingComplex process and takes longer.Simple process and takes less time.
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What is Meiosis I?

The term gets defined as the first main division of the nucleus of the eukaryotic cell during the process of meiosis and has the following stages involved; prophase I, metaphase I, anaphase I and telophase I. We know that it gets defined as the process through which the reproductive cells get formed therefore the meiosis first phase plays a significant role in helping achieve the task. Prophase I gets divided into five other phases where the first one the chromosome coil and contract consist of two chromatids that become combined with the help of something along the length. The next step helps in the point-to-point connection between the homologous chromosome pair. The next stage helps in forming the structure formation known as bivalent. Chromosomes become thick in the fourth phase whereas the last phase they break and rejoin when the process completes. The final stage stays shorter in male and longer in female due to the compound nature. Another thing to note remains the fact that the Meiosis I becomes more complicated as compared to the additional Meiosis II. All the other phases within these two remain the same except for the action where two chromosomes formed during the bivalent do not stay together and start moving in the opposite direction. Because of this action, each daughter cell gets the haploid number of chromosomes that do not have any particular order among them. These two daughter cells divide again to form four cells, and the process keeps repeating until the requirement exists.

What is Meiosis II?

The term gets defined as the last main division of the nucleus of the eukaryotic cell during the process of meiosis and has the following stages involved; prophase II, metaphase II, anaphase II and telophase II. What happens during this phase just becomes the continuation of the first step where the two daughter cells divide again to form four cells that have a chromosome and produce different haploid cells. What happens during the phase goes as the first step, where the formation of spindle fibers takes place within the cell structure. The next step has the chromosomes getting aligned with each other near the plate; the third step helps in dividing the chromosomes and making them double, this helps in them moving from the origin to the poles where the requirement exists. The last stage helps with the haploid breaking, and they convert to four, and the cell breaks from these parts when they start moving I the direction given. Some other actions also take place during the process where the nuclear membrane does not exist anymore during the first stage, the arrangement of particles stays similar to each other during the next, each chromatid becomes a chromosome when they break from the cell. The last part becomes the focus of activity when the four groups already existing become organized and the chromosome return to the original place where they were at the beginning. The number of chromosomes depends on the number of haploids present at the time.

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Key Differences

  1. The term Meiosis I gets defined as the first main division of the nucleus of the eukaryotic cell during the process of meiosis, on the other hand, the term Meiosis II gets defined as the last main division of the nucleus of the eukaryotic cell during the process of meiosis.
  2. Meiosis I has the following stages involved; prophase I, metaphase I, anaphase I and telophase I. On the other hand, Meiosis II has the following steps involved; prophase II, metaphase II, anaphase II and telophase II.
  3. Meiosis I becomes focused on forming the two haploid cells from one diploid cell present. On the other hand, Meiosis II has the task of splitting the sister chromatids present within the haploid cells produced during the first phase of meiosis.
  4. Meiosis I becomes known as a heterotypic division where the parts get reduced whereas Meiosis II becomes known as homotypic division where the parts stay the same.
  5. The number of chromosomes stays the same in Meiosis II whereas the number of chromosomes becomes half in Meiosis I.
  6. Meiosis I takes place for a longer time due to the complex processes that involve during the phases whereas Meiosis II takes place for a shorter time since all the activities stay pure.

Video Explanation

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