Classification of A generalized cell

Ø  Cell Wall: Cell wall is the unique characteristics of a plant cell. The non-living and hard wall, which constructs the plant cell, is called the cell wall. At first Robert Hook observed it in 1665. There is no cell wall in Animal cells.

Ø  Chemical composition of cell wall: The cell wall is mainly composed of cellulose, hemicellulose, pectose, lignin, suberine etc. Those are made by different carbohydrate compound. The cell wall of fungi is made of a carbohydrate called chitin. The cell wall of bacteria made of protein, lipid and polymer.

Ø  Function of cell wall: The functions of cell wall are to give a definite shape to the cell. It protects the Cell from external injury and gives necessary rigidity and to regulate the flow fluid between external and internal side of the cell.

Ø  Protoplasm: Protoplasm is made by the mixture of different complex compounds. It is jelly like, translucent, viscous, colourless semi solid-living substance. All the properties of life are present in it. Protoplasm is divided into three parts: Plasma membrane, Cytoplasm and Nucleus.

Different kinds of Protoplasm:

Ø  Plasma membrane or Cell membrane:Just beneath the cell wall there is a soft living membrane surrounding the whole protoplasm. This is called cytoplasmic membrane or cell membrane.

Ø  Cytoplasm:Outside the nucleus, the part of protoplasm,which is surrounded by the cell membrane, is known as cytoplasm. It is composed of different organic and inorganic compounds like water. different nucleic acid and enzymes. The outer area of cytoplasm is more concentrate. Less  granular and hard, which is called Ectoplasm, and the central area, Which is less concentrated, called Endoplasm. Different organelles like plastids, mitochondria, endoplasmic reticulum, ribosome, golgi bodies, lysosome, centrosome and different nonliving substances are present in the cytoplasm.

 

Ø  Nucleus: Denser and clearer organ found in the protoplasm is Nucleus. Robert Brown discovered and named nucleus in 1831 AD in the cell of orchid leaf. Normally each cell contains one nucleus. Some eukaryotic cell like sieve tube, mature red blood cells of mammal do not have nucleus. Usually nucleus is spherical and present at the centre of the cell. They may be present by the side of a large vacuole. Nucleus may smaller or larger in size and shape.