In Biology, the basic unit of which all living things are composed is known as Cell
Cell – The functional unit of life.
It is the smallest structural unit of living matter that is capable of functioning independently. A single cell can be a complete organism in itself, as in bacteria and protozoans. A unicellular organism also captures and digests food, respires, excretes, grows, and reproduces. Similar functions in multi-cellular organisms are carried out by groups of specialized cells organized into tissues and organs such as the higher plants and animals. Hence, the cell is known as the basic structural and functional unit of life.
All cells have three basic parts:
- A plasma membrane separates each cell from the environment, permits the flow of molecules across the membrane, and contains receptors that can affect the cell’s activities.
- A DNA-containing region occupies a portion of the interior.
- The cytoplasm contains membrane-bound compartments (except bacteria), particles, and filaments.