Try to describe the general process of cell division and what is the most important change? What is the significance of this change?

Mitosis

It is divided into interphase and mitosis. The interphase is mainly to prepare for the division period. It mainly completes the replication of DNA and the synthesis of related proteins.

Prophase of division. The chromosomes gradually shorten and become thicker from thin threads, and are composed of two chromatids intertwined together.

The nucleolus collapses and disappears (the nucleolus of some lower organisms still remains and is divided into two parts into daughter cells).

At the end of prophase, the nuclear membrane breaks into fragments, allowing the chromosomes to be dispersed throughout the cell to the maximum extent possible.

In animal cells, centrioles move to the poles

Metaphase. Mainly completing the structure of the spindle and the arrangement of chromosomes on the equatorial plane. As soon as the nuclear membrane disappears, the spindle appears ,

a. The chromosomes are shortened to the maximum extent and concentrated on the equatorial plane. It is an ideal period for chromosome analysis and counting.

b. The spindle is connected to the centromere of each chromatid and faces the poles.

Anaphase. Sister chromatids separate into independent chromosomes. And connected by spindles, they move toward the two poles, the cells elongate, and the continuous spindles elongate.

Telophase.

When the chromosomes reach the two poles, telophase begins.

a. The nuclear membrane forms and the nucleolus disappears.

b. Chromosomes are loosened into chromatin clumps.

A few points to note.

1. In plant cells, the cell plate, that is, the cell wall, appears at the equatorial plate; in animal cells, the cytoplasm constricts at the equatorial plate, forming two cells. cell. The position of the cell plate and constriction ring is determined by spindle microtubules.

2. In the final stage of animal cells, the cell dents from the center to both ends, constricting the cell into two daughter cells. Reference: Baidu