July 5, 2019
There are two different types of cell division: mitosis and meiosis.
In this article, we are going to take a look at how these two cell division methods are different from each other.
Mitosis
Sometimes, organisms need to produce new cells for:
- growth
- repair of damaged cells
- replacement of old cells
In order to make sure that the newly produced cells are genetically identical to the original cells, the chromosomes are copied and then divided into two identical cells. This type of cell division is called mitosis.
How mitosis happens:
- Each chromosome duplicates, forming 'X' shaped chromosomes.
- Chromosomes line up along the cell's equator.
- One side of each 'X' shaped chromosome is pulled to apart and moves towards the pole.
- The cytoplasm and cell membrane divide, forming two diploid cells that are genetically identical.
* One important terminology to note : Haploid / Diploid *
- Except for gametes (sperm and ova), all cells are diploid. Gametes are haploid.
- Diploid means that each cell carries two sets of the chromosome.
- Haploid means that each cell carries one set of the chromosome.
- For humans, one set contains 23 chromosomes. It means that gametes contain 23 chromosomes and other cells have 46 chromosomes.
Meiosis
Meiosis is the cell division to produce gametes. After meiosis, 4 genetically different cells are produced. The produced gametes are haploid (contain 1 set of chromosomes).
How meiosis happens:
- Meiosis also starts by the duplication of chromosomes and the formation of 'X' shaped chromosomes.
- Similar chromosomes pair up and line up at the equator of the cell.
- At this stage, sections of DNA can get swapped between similar chromosomes.
- During the first cell division, pairs of chromosomes divide, producing two cells.
- The two cells divide once more, producing four haploid cells that are genetically different.
👇 Important to know for IGCSE Biology: Comparison of mitosis and meiosis 👇