Question

What are the three main components of the cell theory?

Answer 1

Hint: Cell is the basic unit structure of living organisms. It is the building block of life. The study of cells is called cytology. The cell is the structural, functional, and biological unit of the living organism. The nucleus is the membrane-bound organelle that consists of the genetic information of an organism. It contains DNA in it.

Complete answer:
The cell theory states that
1. All living organisms are made of cells.
2.Cells are the smallest building blocks of life.
3.Cells arise from pre-existing cells through the process of cell division.
-Schleiden and Schwann gave the cell theory which states that all living organisms are made up of one or more cells, the cell is the basic unit of the life and in an organism new cells tend to arise from the pre-existing cells. In 1838 he said that plant tissues are composed of different cells and the small plant developed from a single cell. Schwann reported that the presence of the cell wall was a unique feature of the plant cell. It was extended by Virchow which states that all the organisms are made up of one or more cells and cells come from pre-existing cells. It is studied that cells emerged on earth about 3.5 billion years ago.

Note:
There are many drawbacks to the cell theory. Through this, the viruses cannot be explained since it is difficult to identify as living or non-living organisms, while on the other hand it Rhizopus is also not explained as they have multinucleated cytoplasm, mature RBC, sieve tube, and so on. However, till now this theory is the most widely accepted one.