What are the Major Parts of Anaphase?

The process of anaphase during mitosis and meiosis is explained as follows:

Mitosis

Anaphase in mitosis involves the separation of sister chromatids, with each chromatid moving to opposite poles of the cell due to the shortening of microtubules attached to kinetochores. The process is explained as follows:

Chromosome Separation

• At the onset of anaphase, the pairs of sister chromatids, which were aligned along the equator of the cell during metaphase, start to separate.
• The enzyme separase cleaves the protein complexes holding the sister chromatids together at the centromere region.

Movement to Opposite Poles

• As enzyme separase cleaves the protein complexes, the sister chromatids become individual chromosomes.
• Microtubules of the spindle apparatus, which are attached to the kinetochores, begin to shorten.
• This shortening pulls the sister chromatids toward opposite poles of the cell.

Formation of Two Groups

• As the sister chromatids move apart, they become visibly separated into two distinct groups.
• Each group contains a complete set of chromosomes identical to the parent cell’s genome.

Cell Elongation

• In animal cells, as the chromosomes are pulled toward opposite poles, the cell may elongate slightly.
• In plant cells, a cell plate begins to form between the two groups of chromosomes, eventually dividing the cell into two daughter cells.

Also Read: Difference between Plant and Animal Mitosis

Meiosis

Anaphase II in meiosis involves the separation of sister chromatids (or homologous chromosomes in meiosis I), with each chromatid (or chromosome) moving to opposite poles of the cell due to the shortening of microtubules attached to kinetochores. Anaphase in meiosis occurs in two stages, Anaphase I and Anaphase II.

Anaphase I

1. Homologous Chromosome Separation
   • In Anaphase I of meiosis, homologous chromosomes, each consisting of two sister chromatids, are separated.
   • This separation results in the segregation of homologous chromosomes into two groups, each containing one chromosome from each homologous pair.
2. Movement to Opposite Poles
   • Microtubules of the spindle apparatus attached to the kinetochores of homologous chromosomes begin to shorten, pulling them toward opposite poles of the cell.
3. Formation of Two Groups
   • As homologous chromosomes move toward opposite poles, they become visibly separated into two groups.
   • Each group contains a haploid set of chromosomes, with each chromosome consisting of two sister chromatids.

Anaphase II

1. Sister Chromatid Separation
   • In Anaphase II, sister chromatids of each chromosome are separated.
   • This separation results in the formation of individual chromosomes, each consisting of a single chromatid.
2. Movement to Opposite Poles
   • Microtubules attached to the centromeres of sister chromatids shorten, pulling them toward opposite poles of the cell.
3. Formation of Two Groups
   • As sister chromatids move toward opposite poles, they become visibly separated into two groups.
   • Each group contains a haploid set of chromosomes, with each chromosome consisting of a single chromatid.

Also Read: Karyokinesis – Phases, Diagram, & Significance

Anaphase is the third phase of mitosis, after metaphase and prophase, when chromosomes split and move to opposite poles of the cell. This ensures each daughter cell receives a complete set of chromosomes. The anaphase diagram shows chromosomes reach their highest level of condensation, which helps with chromosome segregation and nucleus re-formation.

Anaphase’s importance lies in its role in ensuring the correct distribution of genetic material, which is essential for organism development and growth. In this article, we will study anaphase, its structure, parts, and functions as well as some interesting facts about anaphase.