The Fundamental unit of life - Part 1

THE FUNDAMENTAL UNIT OF LIFE

INTRODUCTION :-

• The basic structural and functional unit of life is called as "cell" (latin word) which mean's 'a little room '. 

• cell is discovered by Robert Hooke in 1665 at a slice of a cork of a tree and when he see in the microscope which is made by itself then he saw that it's like a structure of honey comb.

All cell's have some common fundamental feature such as :-

• All cell's have a definite boundary or a cell membrane.
• All cell's have a genetic material as DNA or RNA.
• The structure of cell membrane is same in all cells.
• They have a organ called as Cell Organelle.

CELL THEORY

The cell theory was given by German Botanist Mathias Jacob Schleiden and German Zoologist Theodore Schawnn in 1839.

This theory was also commonly known as Schleiden and Schwann theory.

The concept of this theory are :-

• All living beings are composed of cell
• All cells are basically similar in the chemical composition and perform the metabolic activities.
• All cell's are arise from the pre-existing cell.

Note :-

• This concept was proved experimentally by Louis Pasteur in 1862

UNICELLUALAR AND MULTICELLULAR ORGANISM

UNICELLULAR :-

• Organism consist of single cell 
• The single cell is behaved as whole cell which can perform all the activity.
• The structure is very simple type.
• Ex:- Amoeba, Paramecium.

MULTICELLUALAR :-

• Organism consist of more than one cell.
• They have different organ to perform different activity.
• The structure is very complex type.
• Ex :- Human, Fungi.

SHAPE AND SIZE OF THE CELL

• The cells of different organism are not similar they have different structure according to the different activity and purpose.
• The smallest cell is PPLO i.e Pleuro Pneumonia Like Organism.
• The largest cell is the Ostrich egg.

 TYPE'S OF CELL

There are basically two type's of cell :-

1. Prokaryotic cell
2. Eukaryotic cell 

1. Prokaryotic cell :-

• In this cell true nucleus is absent.
• In this membranous organelle are absent.
• They are primitive type.
• The ribosome are of 70 S type.
• Cell was does not contain cellulose or chitin etc instead of this they have peptidoglycan.
• Genetic material is represent by single circular DNA.
• The cell's are basically divide by Asexual reproduction like binary and multiple fission.

2. Euckaryotic cell :-

• In this true nucleus is present.
• In this double membranous organelle are present.
• They are complex type.
• The ribosome are of 80 S type and attached to Endoplasmic Reticulum (ER)
• Cell contain cellulose or chitin etc as to make cell wall. 
• DNA and genetic material is located inside the nucleus.

ANIMAL CELL AND PLANT CELL   

ANIMAL CELL :-

• They are soft and flexible due to the absence of cell wall.
• Plastid's are absent in this.
• They have a small Vacoule present in the cell.
• Centriole are present in animal cell.

PLANT CELL :-

• The outer membrane is cell wall which make the cell more rigid and strengthen.
• Plastid are present in this.
• They have a large Vacoule present in the cell.
• Centriole are absent in animal cell.