How is chromosome number maintained during mitosis?

Chromosome number is maintained during mitosis through the duplication and equal distribution of chromosomes to two daughter cells.

Mitosis is a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus. This process is crucial for growth, repair, and general maintenance of an organism. The maintenance of chromosome number during mitosis is achieved through a series of carefully coordinated steps.

The process begins in the interphase, where the DNA in the cell's nucleus is duplicated. This results in two identical copies of each chromosome, known as sister chromatids. These chromatids are held together at a region called the centromere. At this stage, even though the DNA has been duplicated, the chromosome number of the cell remains the same because the sister chromatids are still joined together.

As the cell enters mitosis, the sister chromatids are separated and moved to opposite ends of the cell. This is achieved through the formation of a structure called the mitotic spindle, which attaches to the centromeres of the sister chromatids and pulls them apart. This process ensures that each new cell will receive one copy of each chromosome.

Finally, the cell divides into two, each with an identical set of chromosomes. This is known as cytokinesis. At the end of this process, each daughter cell has the same number of chromosomes as the original parent cell.

In summary, the chromosome number is maintained during mitosis through the duplication of DNA during interphase, the separation of sister chromatids during mitosis, and the equal distribution of chromosomes during cytokinesis. This ensures that each new cell has the exact genetic material as the parent cell, maintaining the chromosome number.