Cell division-(Mitosis, Meiosis) full nots…

Cell division

The process of a parent cell dividing into two or more daughter cells, each containing the parent cell’s genetic material, is known as cell division. It is a basic process that enables growth, development, tissue repair, and reproduction in living things. Cell division occurs primarily in two forms: meiosis and mitosis.


The cell division process known as mitosis produces two daughter cells that are genetically identical to their parent cell and have the same number of chromosomes. It is an essential process for the body’s cell population’s upkeep, growth, and repair of damaged tissue. The phases of mitosis that are commonly recognized include prophase, metaphase, anaphase, and telophase.


Under a microscope, condensed chromosomes can be seen.
The nuclear envelope starts to disintegrate.
Microtubule-based spindle fibers develop and stretch between the cell’s two poles.


At the cell’s metaphase plate, or equator, chromosomes align.
Spindle threads cling to each chromosome’s centromeres.


The centromere separates and causes sister chromatids to travel in different directions toward the cell’s poles.
The chromatids are separated by the shortening of microtubules.


Chromatids go to the cell’s poles.
The de-condensation of chromosomes into chromatin commences.
With every pair of chromosomes, the nuclear membrane reforms.
The fibers in the spindle separate.


The division of the cytoplasm and organelles between the two daughter cells occurs during cytokinesis, which comes after mitosis.
A cleavage furrow that pinches the cell in half occurs in animal cells.
Plant cells have a centrally located cell plate that progressively develops into a new cell wall in between the daughter cells.

                             Two identical diploid daughter cells with the same genetic makeup as the parent cell are produced as the end product of mitosis. Multicellular organisms require mitosis to grow and survive. It ensures that damaged or dead cells are replaced and contributes to the general development of tissues and organisms.


Meiosis is a specific kind of cell division that takes place in organisms capable of sexual reproduction. In contrast to mitosis, which creates daughter cells that are genetically identical, meiosis yields cells that have half as many chromosomes as their parent cells. Gametes, or sperm and egg cells, are formed during sexual reproduction, and this decrease in chromosome count is essential for this process.

Meiosis I and Meiosis II are the two consecutive divisions that make up meiosis. Similar to mitosis but with some distinct characteristics, each of these divisions has its own set of stages. Meiosis’s primary phases are:

Meiosis I:

Prophase I: Chromosomes compress, and a process known as synapsis occurs when homologous chromosomes that is, chromosomes with the same genes but perhaps distinct alleles pair up. A tetrad is this pair of people. Genetic recombination comes from crossing-over, the exchange of chromatid segments. As the nuclear envelope degrades, spindle fibers start to develop.

Phase I of metaphase:At the metaphase plate, or equator of the cell, tetrads align. Each homologous chromosome’s centromere is where spindle fibers are attached.

Phase I Anaphase:When homologous chromosomes are pushed apart, they go to the cell’s opposing poles. In contrast to mitosis, at this stage the sister chromatids stay together.

Phase I of Telophase:As chromosomes reach the poles, the nuclear membrane could reorganize. Following cytokinesis, the cell divides into two daughter cells, each of which has half as many chromosomes as the parent cell.

Meiosis II:

Prophase 2:Recondensing chromosomes give rise to a new spindle machinery.

Phase 2 Metaphase:At the equator of the cell, chromosomes align.

Phase 2 of Anaphase:At last, sister chromatids split apart and go to opposing poles.

phase 2 of telophase:When chromatids reach the poles, nuclear envelopes reorganize to encircle the chromosomal sets. After the cells go through cytokinesis, four haploid daughter cells with different genetic combinations are produced.

Significance of Meiosis:

Variations in Genetics:Genetic diversity is introduced during meiosis by means of crossing over and the haphazard distribution of chromosomes during metaphase I.

Gametes with haploid structure:The outcome is the creation of gametes, each of which has half as many chromosomes as the parent cell. Two gametes unite during fertilization, giving the zygote its diploid chromosomal count again.

Preserving Chromosome Number:In order to avoid chromosome counts doubling with each generation, meiosis makes sure that the number of chromosomes in gametes is half.

                             Through mechanisms including crossing-over and independent chromosomal assortment, meiosis creates genetic variation. The resultant gametes add to the genetic variety seen in sexually reproducing creatures, as each one has a distinct mix of genetic material.


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