April 29, 2020
- Understand the importance of cell division in growth and reproduction.
- Outline the processes of mitosis.
Mitotic cell division (Mitosis)
- Mitosis is the nuclear division that a parent cell divides into two identical daughter cells.
HKDSE Biology students have to remember how chromosomes are arranged in different phases of mitosis ❗️ ❕
👆🏻This photo showing different phases in mitosis.
1. Prophase
- Homologous chromosomes undergo condensation.
- Each homologous chromosome consisting two chromatids joined together by centromere.
- Mitotic spindle is generated on each side.
👆🏻This photo showing the situation of cell under prophase.
2. Prometaphase
- The nuclear membrane breaks down.
- Mitotic spindle formed in prophase will attach to the centromere of homologous chromosome.
3. Metaphase
- Mitotic spindle pull the homologous chromosome till they align in a plane.
- The homologous chromosome are located at the centre of the cell due to the movement of mitotic spindle.
👆🏻This photo showing the situation of cell under metaphase.
4. Anaphase
- Chromatids in the homologous chromosome are separated at their centromeres.
- Chromatids are pulled to opposite poles of the cell by mitotic spindle.
- The importance of anaphase 👉🏻 each daughter cell get the same amount of chromosome.
👆🏻This photo showing the situation of cell under anaphase.
5. Telophase
- The nuclear membrane forming back.
- The nuclear membrane enclosing each set of chromosome for each daughter cell.
- Chromosomes start to uncoil and become less compact again.
👆🏻This photo showing the situation of cell under telophase.
Cytokinesis is the last step in mitotic cell division to 100% separate two daughter cell via dividing the cytoplasm. ✌🏻
Importance of mitosis 💫
- Genetic stability - preservation of genetic information from generation (parent cell) to generation (daughter cell).
- Growth - increment on the number of identical cell which is significant for the growth of organism.
- Repair - replacement of damaged cell with new identical cell which is the regrowth in organism.
- Asexual reproduction - e.g. binary fission in amoeba, budding of hydra and yeast.
That's the end of this topic 👏🏻
References
- (n.d.). Retrieved from https://www.nature.com/scitable/topicpage/mitosis-and-cell-division-205/
- Mitosis: Importance, Stages, Examples with Questions & Videos. (2019, November 22). Retrieved from https://www.toppr.com/guides/biology/cell-cycle-and-cell-division/mitosis/