Class 9 Science - Chapter 1: The Fundamental Unit of Life
1. Introduction
All living organisms are made up of tiny units called cells.
The cell is the basic structural and functional unit of life.
Robert Hooke discovered the cell in 1665.
2. Discovery of Cell
Robert Hooke - Discovered cells in cork (1665)
Leeuwenhoek - First to see living cells (1674)
Robert Brown - Discovered the nucleus
Schleiden & Schwann - Gave cell theory
Rudolf Virchow - 'Omnis cellula e cellula' (Cells arise from cells)
3. Cell Structure
Three main parts:
1. Cell membrane - Outer boundary, controls movement
2. Cytoplasm - Jelly-like, site of chemical reactions
3. Nucleus - Controls cell activities
Other organelles:
- Mitochondria: Powerhouse of the cell
- Golgi body: Packaging unit
- ER: Transport system
- Lysosomes: Suicide bags
- Plastids: Only in plant cells (e.g., chloroplasts)
- Vacuoles: Store food, water
4. Difference Between Plant and Animal Cells
Plant Cell:
1. Introduction
All living organisms are made up of tiny units called cells.
The cell is the basic structural and functional unit of life.
Robert Hooke discovered the cell in 1665.
2. Discovery of Cell
Robert Hooke - Discovered cells in cork (1665)
Leeuwenhoek - First to see living cells (1674)
Robert Brown - Discovered the nucleus
Schleiden & Schwann - Gave cell theory
Rudolf Virchow - 'Omnis cellula e cellula' (Cells arise from cells)
3. Cell Structure
Three main parts:
1. Cell membrane - Outer boundary, controls movement
2. Cytoplasm - Jelly-like, site of chemical reactions
3. Nucleus - Controls cell activities
Other organelles:
- Mitochondria: Powerhouse of the cell
- Golgi body: Packaging unit
- ER: Transport system
- Lysosomes: Suicide bags
- Plastids: Only in plant cells (e.g., chloroplasts)
- Vacuoles: Store food, water
4. Difference Between Plant and Animal Cells
Plant Cell:
