Cell Structure, Functions and Working Principle
Author: Mmesoma
Simplified notes to help you ace Biology in JAMB.
1. Introduction to Cells
Cells are the basic units of life. All living organisms are made up of cells, from the simplest bacteria
to complex human beings.
There are two main types of cells:
- Prokaryotic cells (e.g., bacteria): no nucleus.
- Eukaryotic cells (e.g., plants and animals): have a nucleus.
2. Structure of a Typical Cell
Major parts of a cell:
- **Cell membrane**: controls what goes in and out.
- **Cytoplasm**: jelly-like substance where reactions happen.
- **Nucleus**: controls the cell, contains DNA.
- **Mitochondria**: powerhouse of the cell - produces energy.
- **Ribosomes**: make proteins.
- **Endoplasmic reticulum (ER)**: transports materials. (Rough ER has ribosomes, Smooth ER
doesn't).
- **Golgi apparatus**: packages and sends out materials.
- **Lysosomes**: digest waste (mostly in animal cells).
- **Vacuole**: stores materials (big in plant cells).
- **Chloroplasts**: only in plant cells - for photosynthesis.
- **Cell wall**: found in plant cells - gives shape and support.
Author: Mmesoma
Simplified notes to help you ace Biology in JAMB.
1. Introduction to Cells
Cells are the basic units of life. All living organisms are made up of cells, from the simplest bacteria
to complex human beings.
There are two main types of cells:
- Prokaryotic cells (e.g., bacteria): no nucleus.
- Eukaryotic cells (e.g., plants and animals): have a nucleus.
2. Structure of a Typical Cell
Major parts of a cell:
- **Cell membrane**: controls what goes in and out.
- **Cytoplasm**: jelly-like substance where reactions happen.
- **Nucleus**: controls the cell, contains DNA.
- **Mitochondria**: powerhouse of the cell - produces energy.
- **Ribosomes**: make proteins.
- **Endoplasmic reticulum (ER)**: transports materials. (Rough ER has ribosomes, Smooth ER
doesn't).
- **Golgi apparatus**: packages and sends out materials.
- **Lysosomes**: digest waste (mostly in animal cells).
- **Vacuole**: stores materials (big in plant cells).
- **Chloroplasts**: only in plant cells - for photosynthesis.
- **Cell wall**: found in plant cells - gives shape and support.
