Anaphase in Mitosis and Meiosis Definition
This stage separates the genetic material contained in duplicate in the nucleus of the parent cell into two similar daughter cells.
- The sister chromatids (replicated chromosomes) are arranged on the metaphase plate along the equator of the cell in the preceding phase, called metaphase.
- Consequently, during anaphase, every pair of chromosomes separates into two different, identical chromosomes.
- Microtubules, mitotic spindles that are associated to the chromosomes at the cell’s two ends, divide each of these chromosomes.
- Every divided chromosome is attracted to the opposing cell poles by the spindles after separation takes place simultaneously at the centromere.
- Before the cell cycle’s telophase, or final phase, anaphase ensures that every daughter cell receives a similar set of chromosomes.
What happens during anaphase?
- When the anaphase-promoting complex, which terminates the metaphase, is present, anaphase commences.
- Securin, a protein that facilitates the transition from metaphase to anaphase, is also used to degrade itself by accepting ubiquitin tagged by this anaphase-promoting complex, functioning as an inhibitory chaperone.
- The protease enzyme separase, which is how securin works, is inhibited. The cohesin protein, which maintains the unity of sister chromatids, is broken down by the separase enzyme once securin is eliminated.
- The energy required for chromatid detachment is generated by a variety of specialised microtubules. These comprise the interpolar microtubules, astral microtubules, and kinetochore microtubules.
- Consequently, the centromere divides, prompting kinetochore microtubules to drag sister chromatids to the cell poles.
- At each cellular pole, the separated sister chromatids assume the form of a V or a Y.
- The cell takes on an oval form as a result of stretching and shaping by the astral and interpolar microtubules.
- The chromatids that are separated into a single sister chromosome contain identical genetic material, but function differently as distinct cells.
- Once anaphase is effectively concluded, the cell cycle advances to telophase.
Anaphase in mitosis
- The separase-aided separation of the sister chromatids stimulates anaphase during mitosis.
- As the microtubules drive the sister chromatids in the reverse direction of the cell, separase breaks down their cohesiveness.
- The astral and interpolar microtubules are crucial players in elongating and extending the cell, which becomes an oval form.
Anaphase in meiosis
- The anaphase of meiosis consists of the two successive cell divisions, referred to as anaphases I and II.
- Since there is no DNA replication in between, the diploid cell having two alleles for every gene turns into a haploid cell containing a single allele for each gene during this stage of meiosis.
- Anaphase I normally involves the separation of chromosomes from every sister chromatid to the opposite poles while they are still attached to the microtubules of the cell, while anaphase 2 entails the actual splitting of the sister chromatids into single chromatids.
- In this phase, the homologous chromosomes are pulled to the cell’s opposing poles by shortening kinetochore microtubules.
- Centrosomes are forced apart when non-kinetochore microtubules start to lengthen.
- The cell gets longer as it gets ready to split in the middle.
- The protein Shugoshin (guardian spirit), which keeps the cohesins surrounding the centromere shielded while the homologs are segregated, prevents the sister chromatids from splitting.
- The remaining centromeric cohesins that are no longer shielded by the Shugoshin are cleaved during this metaphase 2 phase.
- This makes it possible to separate the sister chromatids, which are subsequently referred to as sister chromosomes when they exist separately. They migrate in the direction of the cell’s antipodal poles.
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