Understand that division of a diploid cell by mitosis produces two cells which contain identical sets of chromosomes.
Mitosis - cell division which results in growth which occurred by increase in number of cell
A normal cell with its nucleus. The number of chromosome in the nucleus is called the diploid number (abbreviated 2n). For human, 2n = 46.
In the process known as mitosis, a cell will divide into two cells, each with a nucleus. Each nucleus contains diploid number of chromosomes. The two cells are identical in which sometimes are described as daughter cells.
- They have the same number of chromosomes.
- They have the same set of chromosomes.
How are the copies of chromosomes made? How did they separate into two cells?
The original cell has to copy its chromosomes in the process called DNA replication. In this process, each chromosome undergrowth and copy process to form an identical copy of the cell with the same genes and same alleles. The two copies are held together by a structure around the center region known as the centromere. The pair is called pair of chromatids.
The process of DNA replication takes place inside the nucleus while it's still intact. This resting stage of cell cycle is known as the interphase.
The Stages of Mitosis
During the interphase, the process of DNA replication occurs. We are not able to observe the chromosomes.
1. Prophase: Nuclei member breaks down and the chromosomes become visible as a pair of chromatids.
2. With the nucleus gone, inside the cell, a network of protein molecules known as the spindle/ spindle fibres formed. This extends from one pull of the cell to the other. Late prophase: The chromosome pairs will move toward the spindle and will join with the spindle fiber in the center.
3. Metaphase: The pair of chromatids are attached to the spindle fibre by the centromere. The characteristic is the chromosomes are in the middle across the equator of the cell.
4. Anaphase: The spindle fiber shortened, pulling each chromosome in opposite direction and the pair of chromatids are moving apart toward each poles. (They're separated.)
5. Telophase: The nucleus beings to reform around chromosomes at either end of the cell. (The formation of two nuclei at opposite ends of the cell.)
6. Cytokinesis: The cell splits into two. This is NOT part of mitosis. It is a particular independent stage.
The daughter cells each contain a chromosome, which is the same as the parental cell. In human cell, we see 23 pairs of chromosomes separating at the same time.
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