NEET BIOLOGY

Detailed explanation-1: -The classical cell theory was proposed by Theodor Schwann in 1839. There are three parts to this theory. The first part states that all organisms are made of cells. The second part states that cells are the basic units of life.

Detailed explanation-2: -The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells. Rudolf Virchow later made important contributions to this theory.

Detailed explanation-3: -Cell biology is the study of cell structure and function, and it revolves around the concept that the cell is the fundamental unit of life. Focusing on the cell permits a detailed understanding of the tissues and organisms that cells compose.

Detailed explanation-4: -Cell theory also states that cells are the basic functional unit of living organisms and that all cells come from other cells.

Detailed explanation-5: -The cell is the basic unit of life indicates that it is the smallest unit considered to be alive. For example, DNA can be replicated outside of the cell, but DNA itself is not considered to be alive. Organisms can be composed of one (unicellular) or many (multicellular) cells.