Question

What is cytokinesis and when does it occur?

Answer 1

Hint: In a cell, a sequence of events takes place where the cell genome duplicates and the cell divides into two daughter cells. In cell division the first division of the nucleus takes place and later the cell divides into two more daughter cells consisting of equal amounts of cell organelles.

Complete answer:
In cytokinesis, the division of cytoplasm takes place where the parent cell divides into two daughter cells. It occurs at the mid of anaphase and is completed with the telophase.
In animals and plants, the occurrence of cytokinesis is different. In animals, the cell divided by making a furrow and the central part of the spindle gets changed into a fibrous structure mid-body. The furrow deepens medically and gets divided into two daughter cells from a single parent cell. During division, the midbody of the cell gets compressed and smaller and finally disappears forming the two fully formed cells. This type of cytokinesis is known as cleavage cytokinesis.
In plants, cytokinesis takes place by cell wall formation. The equator gets lined up with the small vesicles produced by the Golgi apparatus and the membranes of vesicles fuse to form a plasma membrane. With the formation of the cell plate, the spindle disappeared. The cell plate in the plant is made up of cellulose, hemicellulose and pectin and after the division, this deposit on the middle lamella side and helps in the formation of the primary cell wall.

Note:
Cleavage cytokinesis is also shown by lower organisms like bacteria, fungi and some algae. This type of cytokinesis is not shown by plants due to the presence of rigid cell walls, the plant cell is not able to make the furrow therefore the plant cell divides by forming a cell plate.