What is Photosynthesis?
✅ Definition:
Photosynthesis is the process by which green plants, algae, and some bacteria use sunlight to make their own food (glucose) from carbon dioxide and water.
📌 It’s how plants turn light energy into chemical energy.
💡 Why is Photosynthesis Important?
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Produces oxygen that we breathe
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Provides food and energy for all living things
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Begins the food chain
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Removes carbon dioxide from the air
🔬 Where does it happen?
Photosynthesis occurs mainly in the leaves of plants, in tiny structures called chloroplasts, which contain a green pigment called chlorophyll.
🌱 Chlorophyll absorbs sunlight — especially red and blue light — and gives leaves their green color.
🧪 Photosynthesis Equation (Simplified):
6 CO2+6 H2O+light energy→chlorophyllC6H12O6+6 O2\text{6 CO}_2 + \text{6 H}_2O + \text{light energy} \xrightarrow{\text{chlorophyll}} \text{C}_6\text{H}_{12}\text{O}_6 + \text{6 O}_2
What it means:
| Ingredient | Role |
|---|---|
| CO₂ (carbon dioxide) | Comes from the air |
| H₂O (water) | Comes from the soil via roots |
| Light energy | From the sun |
| Chlorophyll | Helps absorb light |
| C₆H₁₂O₆ (glucose) | Plant’s food (sugar) |
| O₂ (oxygen) | Released into the air |
🌞 The Two Stages of Photosynthesis:
| Stage | What Happens | Needs Light? |
|---|---|---|
| Light-dependent reaction | Light splits water into oxygen & energy (ATP, NADPH) | ✅ Yes |
| Light-independent reaction (Calvin Cycle) | Uses CO₂ + energy to make glucose (sugar) | ❌ No |
🌱 Simple Summary:
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Plants take in sunlight, CO₂, and water
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They produce glucose (food) for energy
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They release oxygen as a “waste” product
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All this happens in chloroplasts in leaves
🧠 Fun Facts:
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Plants make millions of tons of oxygen every day
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Photosynthesis removes carbon dioxide, helping fight climate change
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Some algae do more photosynthesis than all land plants combined!
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It is the basis of almost all life on Earth
📌 Quick Review Table:
| Question | Answer |
|---|---|
| What is photosynthesis? | Process where plants make food using sunlight |
| Where does it occur? | In chloroplasts (mostly in leaves) |
| What does it need? | CO₂, H₂O, sunlight, chlorophyll |
| What does it produce? | Glucose (C₆H₁₂O₆) and oxygen (O₂) |
| Why is it important? | Produces oxygen & food; removes carbon dioxide |