Photosynthesis – Food-Making Process In Plants
Key Notes :
Definition of Photosynthesis:
- Photosynthesis is the process by which green plants make their own food using sunlight, carbon dioxide, and water.
Raw Materials Needed:
- Carbon dioxide (CO₂): Absorbed from the air through small pores called stomata in leaves.
- Water (H₂O): Absorbed from the soil by roots.
- Sunlight: The energy source for the process.
- Chlorophyll: The green pigment in leaves that captures sunlight.
The Process of Photosynthesis:
Takes place in the chloroplasts of plant cells.
Involves a chemical reaction:
Glucose (C₆H₁₂O₆) is produced as food, and oxygen (O₂) is released as a by-product.
Role of Chlorophyll:
- Chlorophyll absorbs sunlight, which provides the energy needed to combine carbon dioxide and water.
Importance of Sunlight:
- Acts as the energy source to drive the chemical reactions in photosynthesis.
Products of Photosynthesis:
- Glucose: Used as energy for the plant or stored as starch.
- Oxygen: Released into the atmosphere, essential for respiration in animals and humans.
Significance of Photosynthesis:
- Provides food and energy for plants, animals, and humans.
- Helps maintain the oxygen-carbon dioxide balance in the environment.
- Supports the food chain as plants are primary producers.
Factors Affecting Photosynthesis:
- Light intensity: More light increases the rate of photosynthesis.
- Carbon dioxide levels: Higher CO₂ levels boost photosynthesis.
- Water availability: Insufficient water can slow or stop the process.
- Temperature: Extremely low or high temperatures can inhibit photosynthesis.
Adaptations of Leaves for Photosynthesis:
- Broad surface area: Maximizes sunlight capture.
- Thin structure: Ensures efficient gas exchange.
- Chloroplasts: Contain chlorophyll for trapping light energy.
Applications in Real Life:
- Basis of agriculture and crop production.
- Helps in reforestation and maintaining ecological balance.
- Contributes to oxygen generation for the survival of all living beings.
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