Photosynthesis
What Is Photosynthesis?
Photosynthesis is the process plants use to make glucose (food) using light energy. It takes place in the chloroplasts of plant cells, which contain chlorophyll.
💡 Key Concept: Photosynthesis converts light energy into chemical energy, which is stored as glucose.
The Photosynthesis Equation
Word Equation:
🌿 Carbon dioxide + Water → Glucose + Oxygen
☀️ (Light energy & chlorophyll needed!)
Symbol Equation:
6CO2+6H2O→C6H12O6+6O2
💡 Key Fact: Oxygen is a waste product of photosynthesis.
Where Does Photosynthesis Happen?
✔ Takes place in the chloroplasts of leaf cells.
✔ Chlorophyll absorbs light energy to drive the reaction.
Leaf Adaptations for Photosynthesis:
|
Adaptation |
How It Helps |
|
Large surface area |
More light absorbed. |
|
Thin leaves |
Short distance for gases to diffuse. |
|
Chloroplasts (with chlorophyll) |
Absorb light energy. |
|
Stomata (tiny holes) |
Allow gas exchange. |
|
Xylem & Phloem |
Transport water and glucose. |
💡 Why Is This Important? These adaptations increase the rate of photosynthesis, helping plants grow faster.
Why Is Photosynthesis Important?
✔ Provides oxygen for respiration.
✔ Creates glucose for plant growth and energy.
✔ Removes CO₂ from the atmosphere.
✔ Supports food chains by making energy available to herbivores.
💡 Example: Plants store glucose as starch, which can be tested using iodine solution (turns blue-black if starch is present).
Questions
- What is the word equation for photosynthesis?
- Where does photosynthesis occur?
- What is the role of chlorophyll?
- Name one adaptation of a leaf for photosynthesis.
- Why is photosynthesis important for animals?
Summary
- Photosynthesis converts light energy into glucose using carbon dioxide and water.
- It takes place in chloroplasts, where chlorophyll absorbs light.
- Leaves are adapted to maximise photosynthesis efficiency.
- Photosynthesis produces oxygen and glucose, supporting life on Earth.