Notes, Exercises, Videos, Tests and Things to Remember on Mitosis Cell Division
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Points to remember:
Cytokinesis: The change that occurs in the cytoplasm (cell membrane) during the process of cell division is called cytokinesis. Anaphase and telophase of cell division lie under cytokinesis.
Karyokinesis: The change that occurs in chromosome during the process of cell division is called karyokinesis. All four stage of cell division i.e. prophase, metaphase, anaphase and telophase fall under karyokinesis.
The incidents that take place during the prophase stage of mitotic cell division are:
i. The chromosomes coil, shorten and become distinct.
ii. Each chromosome divides longitudinally to form two chromatids that are held together by a centromere.
iii. In animal cells, the centrioles divide and move towards opposite poles.
iv. Nucleons and nuclear envelop begin to disappear.
The incidents that occurred at anaphase of mitotic cell division are:
a. The spindle fibers contract.
b. The centromere splits.
c. The chromatids separate.
d. The chromatids move to opposite poles.
The significances of mitotic cell division are:
a. It is used for growth and development of an organism.
b. It is important for asexual reproduction in lower organism.
c. As the daughter cells are identical to each other and to the mother cell, mitotic cell division maintains genetic stability in organisms. d. It is important for replacing the dead and damaged cells.
During interphase of mitosis, each chromosome is replicated. So, instead of having normal diploid (2n) chromosomes, the cell has tetraploid (4n) chromosomes temporarily. During Telophase, the chromosomes get divided into two groups and then cell gets equal number of chromosomes as that of mother cell.
1. It occurs in Prophase. In this phase, the chromosomes coil, shorten and become invisible.
2. It occurs in Telophase. In this phase, the chromosomes uncoil and become entangled.
3. It occurs in Metaphase. In this phase, the chromosomes are connected by the spindle fibers at their centromere.