Anaphase of Mitosis and Meiosis (Anaphase I, II), Diagram

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Definition of Anaphase

This is the phase in which the two identical daughter cells are separated from duplicate genetic components carried in the nucleus of the parent cell.

The sister chromatids (replicated chromosomes) are oriented along the cell’s equator on the metaphase plate in the preceding phase, metaphase.
As a result, each pair of chromosomes divides into two identical but independent chromosomes during anaphase.
Mitotic spindles known as microtubules, connected to the chromosomes at both ends of the cell, separate each of these chromosomes.
At the centromere, chromosomal separation happens simultaneously, and the spindles drag each divided chromosome to the opposing poles of the cell.
Anaphase’s purpose is to ensure that each daughter cell receives identical sets of chromosomes before the cell cycle’s last phase, telophase.

What happens during Anaphase?

The anaphase-promoting complex, which ends the metaphase, initiates anaphase.
This anaphase-promoting complex binds to securin, a protein that aids in the transition from metaphase to anaphase and is also employed to destroy securin by absorbing ubiquitin, thereby functioning as a chaperone inhibitor.
Securin works by blocking a protease enzyme called separase. When securin is degraded, the separase enzyme is activated, which breaks down the cohesin protein that keeps the sister chromatids together.
The forces required for the separation of chromatids are created by a number of different microtubules. Astral microtubules, kinetochore microtubules, and interpolar microtubules are among them.
The centromere splits, causing the sister chromatids to be pulled to the cell poles by the kinetochore microtubules.
At either pole of the cell, the divided sister chromatids form a V or Y shape.
The stretching and shaping of the cell, which takes on an oval shape, is aided by astral and interpolar microtubules.
When chromatids are separated into single sister chromosomes, they contain the same genetic information but operate as separate cells.
The cell cycle moves on to the following phase, telophase, after anaphase is completed.

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Anaphase of Mitosis

The separation of the sister chromatids with the help of separase initiates anaphase in mitosis.
As the microtubules drag the sister chromatids towards the opposite ends of the cells, Separase destroys the cohesion that keeps them together.
The astral and interpolar microtubules are responsible for the cell’s oval form by extending and elongating it.

Anaphase of Meiosis

Meiosis’ anaphase is made up of two successive cell divisions, known as anaphase I and anaphase II.
Since there is no DNA replication at this stage of meiosis, the diploid cell with two alleles for each gene is reduced to a haploid cell with a single allele for each gene.
Anaphase I entails separating the chromosomes from each sister chromatid to the opposite poles, which are still linked to the cell’s microtubules, whereas anaphase 2 entails splitting the sister chromatids into single chromatids.

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Anaphase I

Figure: Anaphase I in Meiosis. Image Source: Wikipedia

The kinetochore microtubules shorten during this phase, pulling homologous chromosomes to opposing poles of the cell.
The centrosomes are pushed apart as the non-kinetochore microtubules lengthen.
As it prepares to divide at the middle, the cell also lengthens.
A protein known as Shugoshin (guardian spirit) protects the cohesins surrounding the centromere, preventing sister chromatids from splitting when homologs are segregated.

Anaphase II

Figure: Anaphase II in Meiosis. Image Source: Wikipedia

After metaphase 2, this is the phase in which the remaining centromericcohesins that are no longer protected by the Shugoshin are cleaved.
This permits the sibling chromatids to be separated and referred to as sister chromosomes individually.
They travel towards the cells’ opposite poles.

Anaphase of Mitosis and Meiosis Citations

com/Biology For Major
https://teaching.ncl.ac.uk/bms/wiki/index.php/Anaphase
https://www.nature.com/scitable/definition/anaphase-179/
https://en.wikipedia.org/wiki/Meiosis#Anaphase_I
https://en.wikipedia.org/wiki/Anaphase
https://www.khanacademy.org/science/biology/cellular-molecular-biology/mitosis/a/phases-of-mitosis

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