1. Introduction: It is the process by which a mature cell divides and forms two nearly equal daughter cells which resemble the parental cell in a number of characters.
2. Discovery: Prevost and Dumas (1824) first to study cell division during the cleavage of zygote of frog.
3. Nagelli (1846) was the first to propose that new cells are formed by the division of pre-existing cells.
4. Rudolf virchow (1859) proposed “omnis cellula e cellula” and “cell lineage theory”.
5. A cell divides when it has grown to a certain maximum size which disturb the karyoplasmic index (KI)/Nucleoplasmic ratio (NP)/Kernplasm connection.
6. Two processes take place during cell reproduction.
7. Cell cycle: Howard and Pelc (1953) first time described it. The sequence of events which occur during cell growth and cell division are collectively called cell cycle. Cell cycle completes in two steps:
8. Duration of cell cycle: It depends on the type of cell and external factors such as temperature, food and oxygen. Time period for G1, S, G2 and M-phase is species specific under specific environmental conditions. e.g. 20 minutes for bacterial cell, 8-10 hours for intestional epithelial cell, and onion root tip cells may take 20 hours.
9. Regulation of cell cycle: Stage of regulation of cell cycle is G1 phase during which a cell may follow one of the three options.
10. Cell division is of three types, Amitosis, Mitosis and Meiosis.
11. Difference between cell Mitosis and Meiosis
12. Types of Mitosis
Types of meiosis: On the basis of time and place, meiosis is of three types
1. What is the cell cycle and why is it important for cell division? |
2. What are the different phases of the cell cycle? |
3. How is the cell cycle regulated? |
4. What happens during mitosis? |
5. What are the consequences of abnormal cell cycle regulation? |
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