Profile
Settings
Refer your friends
Sign out
Anaphase is related to cytology, a branch of biology that studies cell structure and cell division. Anaphase is the fourth phase of mitosis, the process by which a parent cell’s replicated genetic material is separated into two identical daughter cells from its nucleus. The sister chromatids, which are replicated chromosomes, are oriented along the equator of the cell on the equatorial plane before anaphase begins. Sister chromatids are DNA pairs that are linked at the centromere.
Each chromosome pair is split into two identical, independent chromosomes during anaphase. A structure known as the mitotic spindle is responsible for separating the chromosomes. The mitotic spindle is made up of microtubules, which are long proteins connected to chromosomes on one end and the cell pole on the other. At their centromeres, the sister chromatids are split at the same time. The spindle then pulls the divided chromosomes to opposite poles of the cell.
Anaphase guarantees that each daughter cell has the same set of chromosomes, and it is followed by telophase, the fifth and final phase of mitosis.
Cell Division is of Two Types
Mitosis (Equational Division)
New cells have an equal number of chromosomes.
This division occurs in haploid (n) and diploid (2n).
This division occurs in somatic cells.
One cell creates two cells.
It helps in the growth and regeneration of body parts.
Examples: body growth, hair growth, cell repairing.
Mitosis is further divided into two phases: interphase and M-phase.
Interphase has G1-phase, S-phase and G2-phase. While M-phase has prophase, metaphase, anaphase and telophase.
Meiosis (Reductional Division)
New cells have half the number of chromosomes.
This division occurs in diploid (2n) and ploidy organisms.
This division occurs in gametic cells.
One cell creates four daughter cells.
It only helps in the formation of gametes.
Examples: sperm creation in human males and ova or egg creation in human females.
Anaphase-II
This phase in meiosis-II comes after metaphase-II, similar to normal mitosis.
In anaphase-II, the ploidy of chromosomes is half (assume if the parent cell has 2n ploidy, then after meiosis-I, the ploidy is n).
There is a cellular checkpoint in this phase that makes sure chromosomes formed after meiosis-I have no changes. If it fails to carry out this function, it can lead to a disjunction of chromosomes which causes polyploidy and aneuploidy that can lead to conditions like Down’s syndrome and Turner syndrome.
Here, the centromere of each chromosome starts splitting up. This splitting pushes the chromosomes to opposite poles.
In anaphase-II, the centromere is V or Y shaped on opposite poles.
Features of Anaphase-I
It occurs in meiosis-I and mitosis but takes place after metaphase-I.
During metaphase-I, the homologous chromosomes align at the metaphase plate.
Each chromosome starts pulling towards opposite poles as the microtubules develop the tension.
In anaphase-I, chromosomes reach opposite poles.
This phase paves the way for telophase-I.
Difference Between Anaphase-I and Anaphase-II
Cell Division Terminology
Cytokinesis: Cyto means cytoplasm, kinesis means division. The process in which the cytoplasm is divided.
Karyokinesis: Karyo means nucleus, kinesis means division. The process in which the nucleus is divided.
(Cytokinesis + Karyokinesis = Cell Division)
Nucleus: The cell organelle that carries the DNA.
Chromosomes: Long, thread-like structures that contain DNA and proteins.
Haploid(n): It represents a single set of chromosomes present in a cell.
Diploid(2n): It represents a double set of chromosomes present in a cell.
Microtubules: It is a cytoskeleton made up of tubulin proteins.
Spindle Fibre: It is a proteinaceous structure that helps attach chromosomes.
Kinetochore: A protein-based disc-shaped structure that helps attach chromosomes and spindle fibre.
Centromere: The centre of the chromosomes where the kinetochore is attached to X-shaped chromosomes.
Conclusion
Anaphase-II is a part of meiosis-II, and it comes after metaphase-II, which is similar to normal mitosis. In anaphase-II, the ploidy of chromosomes is half (assume if the parent cell has 2n ploidy, then after meiosis-I, the ploidy is n). There is a cellular checkpoint in this phase that makes sure chromosomes formed after meiosis-I have no changes. If it fails to carry out this function, it can lead to a disjunction of chromosomes which causes polyploidy and aneuploidy that can lead to conditions like Down’s syndrome and Turner syndrome.
