Cell Division by Mitosis and Meisosis
Cell Division by Mitosis and Meisosis
Cell Division by Mitosis:
- Mitosis is a type of cell division that produces two genetically identical cells from a single cell. These are known as ‘daughter’ cells.
- During mitosis, the cell cycle refers to the phases that the cell goes through: interphase, prophase, metaphase, anaphase and telophase.
- Interphase is the phase in which the cell is preparing to divide, vital processes such as DNA replication occur at this stage.
- The prophase sees the DNA condense into chromosomes and the nuclear envelope breaks down.
- During metaphase, the chromosomes align in the middle of the cell, preparing for separation.
- Anaphase follows with the separation of the sister chromatids, which are pulled apart by spindle fibres to opposite poles of the cell.
- Lastly, telophase sees the formation of two separate nuclei in the newly formed cells.
- Mitosis is a continuous process of growth and repair in the body.
Cell Division by Meiosis:
- Meiosis is a type of cell division that produces four non-identical cells. This process is integral for sexual reproduction.
- It consists of two divisions and results in the formation of haploid cells, which contain half the number of chromosomes (23 in humans) compared to the original cell.
- These resulting cells, gametes, have variation in their genetic information, which is key in biodiversity and evolution.
- During prophase I of meiosis, homologous chromosomes pair up and exchange genetic material. This is called crossing over and leads to genetic variation.
- During anaphase I, homologous chromosomes are separated, breaking the earlier formed pairs.
- Meiosis II separates the sister chromatids into individual cells.
- Random assortment during meiosis also leads to genetic variation. This is because the alignment of homologous chromosomes in metaphase I is random.
Bear in mind that understanding the various stages and the role of each in both mitosis and meiosis will be vital in navigating any related topics. With focus and consistent revision, these concepts will be grasped seamlessly.