[TNPSC Biology Study Materials] The Cell - Basic Unit of Life - TNPSC Biology Study Materials Free Download

The Cell - Basic Unit of Life - TNPSC Biology Study Materials, Notes Free Download

The Cell

"The Cell is a basic Structural and functional unit of all living organisms"

The word 'Cell' in latin 'cellula' means - Small chamber.

Example: Human being is an organism. Humans have many organsystems like digestive system, circulatory sytem etc., Each organsystems has many organs, like in digestive sytem it comprises of organs like stomach, oesophagus, liver, etc., Each organ is made up of tissues. Each tissue is made up of cells. so it is clear that cell is like a brick (basic building block of a life) of a house (Organism).
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Facts to Remember

1. Cell was Discovered by - Robert Hooke in 1665. [Treaty of Purandar signed in 1665 between Jai Singh 1, commander of Mughal and Shivaji]
2. The word Cell was coined by - Rober Hooke
3. The first Living cell was discovered by Anton van Leeuwenhoek in 1674.
4. Robert hooke discovered the cell wall of a wooden cork.
5. Cell Theory was postulated by Theodar Schwann and Matthias Jacob Schleiden in 1839. The two important postulates are
1. All Living Cells are made up of Cells
2. New cells are formed only from the pre-existing cells

Classification of Cell

A Cell can be classified into two types

1. Prokaryotic Cells (Lacks a well defined Nucleus)
2. Eukaryotic Cells (has well defined Nucleus)

Prokaryotic Cells 

• The Word Pro means - primitive, Karyotic - Nucleus. 
• Also called as Simple Cells
• These cells do not have membrane bound organelles and well defined nucleus. 
• Example: Bacteria

Eukaryotic Cells

• The word Eu means - True
• Also called as complete cells.
• These cells have a well defined nucleus, nuclear membrane and membrane bound organelles.
• Example: Plants and animal Cells

Parts of a Cell

A Cell consists of different parts or organelles. Let us see below some of the important parts of a cell.

1. Plasma Membrane
2. Protoplasm
3. Cytoplasm
4. Nucleus
5. Mitochondria
6. Golgi Bodies
7. Endoplasmic Reticulam
8. Ribosomes
9. Lysosome
10. Centrosome
11. Vacuoles
12. Plastids
13. Cell Wall 

The functions of these organelles will be updated soon.