Cells are the basic structural and functional unit of living organism. It can seen only under a microscope. Inside the cell many tiny particles called cell organelles. These organelles are responsible for providing needs of the cell. Cell membrane is a protector. Mitochondria is a powerhouse of the cell. In plants chloroplast is a food producers. Lysosomes are digestive componenets of the cell, Endoplasmic reticulum synthesise protein, Iipid and steroids. Nucleus is the brain of the cell.

Plant and animal cells have a nucleus inside the cytoplasm. It is surrounded by a nuclear envelope. One or two nucleolus and the chromatin body are present inside the nucleus. During cell division the chromatin body is organised in a chromosome

Cell, tissue, organ, organ system, organism

Smooth ER and Rough ER

Cell wall and Cell membrane

Chloroplast and Mitochondria

The building wall is made up of numerous bricks. In similar manner, all living organisms made up of cell. Cell is the fundamental life of organism. So cell is very important for us.

This is Animal cell. The boundary of the cell is known as cell membrane. Inside the cell membrane many tiny organelles present in the cytoplasm. The cell organelles are golgi apparatus, Lysosomes, Ribosomes, Rough and Smooth endoplasmic reticulum, mitochondria and nucleus, Mitochondria is the power house of the cell. The energy produced with in the mitochondrian is used for all the metabalic activities of the cell. Lysosomes are called as suicidal bags because they are the main digestive compartments. Endoplasmic reticulum synthesis of protein lipid and steriods. Nucleus is the brain of the cell. It controls all the processes of chemical reactions that take place inside the cell.

(i) Golgi Complex:
Membrane bounded sacs are stacked on top of the other with associated secretory vesicles are collectively known as golgi complex. Functions of golgi complex are the production of secretory substances, packaging and secretion. This is the secret behind the change in the colour and taste of fruits.
(ii) Lysosome:
You will find organelles called as lysosomes, which are very small to view using a light microscope. They are the main digestive compartments of the cell. They lyse a cell, hence they are called "suicidal bag".
(iii) Nucleus:
Plant and animal cells have a nucleus inside the cytoplasm. It is surrounded by a nuclear envelope. One or two nucleolus and the chromatin body are present inside the nucleus. During cell division, the chromatin body is organised into a chromosome. Storage of genetic material and transfers heredity characters from generation to generation are the functions of chromosome.

Virus is called Acellular because they are not built up out of cells. They are much smaller than cells.
They reproduce only in the living host cells. So virus is called Acellular organisam.