Cell

 Cell is a structural and functional unit of living organism. It is called structural unit because it forms structure of body. Examples, similar cell forms tissue, different tissues forms organ, different organ forms system and different systems forms whole cell. 

It is called functional unit because it perform all of the physiological process in life. For example, 

Growth by cell division

Reproduction

Energy production by metabolism

Carrying of inheritence property

Enzyme and hormone production

Cell consists with different organalie and each organalie have each function

Mitochondria produces energy through metabolism,  DNA in nucleus carries genetic information,  cell division,  

Cytoplasm a plasma like semi liquid elements contains other organalie and gives cell structure, 

Endoplasmic reticulum covered by tiny dot like ribosome that synthesis protein. ER shapes the protein by folding. It packs the protein in small sac and transport to golgi body. 

Ribosome synthesize protein, it can read genetic code and can drop amino acid in exact position. 

Golgy body acts as post office in cell, Its bag like structure packages protein and lipid and transport it to inside and outside of cell. 

Lysosome act as waste manager and recycle centre by waste breaking down, autophagy, phagocytosis, apoptosis

Cell is envelloped by cell membrane.  Though,  plant cell have an excessive cell wall. 

Cell are in two class

Prokaryotic cell: Cell with non structured nucleus. Just like bacteria,  algae,  Amoeba

Eukaryotic cell: Cell with structured nucleus. 

There have,  some specialized cell

RBC WBC,  Mast cell,  Cardiac cell,  Neuron