Question

Cell is the basic unit of life. Discuss in brief.

Answer 1

Hint: The cell is the smallest basic structural, functional, and biological unit of life found in living organisms. All organisms are composed of cells. Those organisms which are composed of single cells are called unicellular organisms. Those organisms which are composed of multiple numbers of cells are called multicellular organisms.

Complete answer:
Cell is the smallest and fundamental unit of life.
Anton Von Leeuwenhoek first described a living cell.
The invention and advancement in the microscope play a leading role in understanding more about cells and its structure.

In 1838 Matthias Schleiden, a german botanist examined a large number of plants and observed that all plants are composed of different kinds of cells which form the tissues of plants.

Theodore Schwann a British zoologist studied different types of animal cells.
Rudolf Virchow gave the cell theory on the basis of the studies of the Schleiden and Schwann hypothesis.

He gave the final theory as
- All living organisms are made up of cells and products of cells.
- All cells arise from pre-existing cells.

Inside each cell has a dense membrane bond structure called nucleus.
This nucleus contains the chromosomes which in turn contain the genetic material named as DNA.
Cells that have membrane bond nucleus are eukaryotic whereas cells that lack a membrane bond nucleus are called prokaryotic cells.

Beside the nucleus, the eukaryotic cells have other membrane bond structures called organelles such as:
- Endoplasmic reticulum
- Golgi bodies
- Mitochondria
- Ribosome
- Lysosomes
- Vacuoles
- Microbodies

Function of cell is:
- Cell provide structure for the body
- Cells take in nutrients from food and convert those nutrients into energy, and carry out specialized functions.
- Cells also contain the body's hereditary material and can make copies of them.
- Cells have many parts and each with a different function.

Note: Plastids are double-membrane organelle which is present in the plant cell. They help in production and storing of food. They often contain pigments that are used in photosynthesis. These types of pigments in a plastid determine the cell's color.