A cell is the basic unit of life.
All living things — plants, animals, bacteria, and humans — are made up of cells.
🔹 Some organisms (like bacteria) are made of one single cell (unicellular).
🔹 Others (like humans) are made of trillions of cells (multicellular).
🧬 Main Types of Cells
| Type | Description | Example |
|---|---|---|
| Prokaryotic | Simple, no nucleus | Bacteria |
| Eukaryotic | Complex, has a nucleus | Plant, animal cells |
🧱 Basic Parts of a Cell (Eukaryotic)
| Part / Organelle | Function |
|---|---|
| Cell Membrane | Controls what enters and leaves the cell |
| Cytoplasm | Jelly-like fluid where organelles are suspended |
| Nucleus | The “brain” of the cell; contains DNA |
| Mitochondria | The “powerhouse”; produces energy (ATP) |
| Ribosomes | Make proteins |
| Endoplasmic Reticulum (ER) | Transports materials inside the cell |
| Golgi Apparatus | Packages and ships proteins |
| Lysosomes | Break down waste (mostly in animal cells) |
| Chloroplasts | Photosynthesis (only in plant cells) |
| Cell Wall | Gives structure and support (only in plant cells) |
| Vacuole | Stores water, food, and waste (large in plants) |
🌱 Differences Between Plant and Animal Cells
| Feature | Plant Cell | Animal Cell |
|---|---|---|
| Cell wall | ✅ Present | ❌ Absent |
| Chloroplasts | ✅ Present | ❌ Absent |
| Shape | Usually rectangular | Usually round |
| Vacuole | One large | Many small |
🔁 What Do Cells Do?
Cells:
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🧠 Control body functions
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💪 Help in growth and repair
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🦠 Fight infections (white blood cells)
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🌿 Perform photosynthesis in plants
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⚡ Create energy from food (cell respiration)
🔬 Fun Facts About Cells
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The average human body has about 37 trillion cells!
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The largest cell is the ostrich egg.
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Some bacteria can live in boiling water or frozen ice — still as single cells.
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Red blood cells have no nucleus!
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The DNA inside a single human cell is about 2 meters long when stretched out.