Photosynthesis and Plant Growth

Overview

• Photosynthesis is essential for plant growth and survival.
• Takes place in the leaves, specifically within chloroplasts.
• Chlorophyll in chloroplasts absorbs light (energy packets) to convert carbon dioxide and water into glucose and oxygen.

Photosynthesis Reaction

• Chemical Equation: 6 CO2 + 6 H2O → C6H12O6 + 6 O2
• Light energy is required for the reaction (endothermic reaction).

Reactants and Products

• Carbon Dioxide: Enters leaves through the stomata.
• Water: Absorbed by roots and transported via the xylem.
• Glucose: Main product, essential for plant energy and growth.
• Oxygen: By-product, sometimes used for respiration.

Uses of Glucose

1. Cellular Respiration:
   • Breaks down glucose to release energy.
   • Glucose acts like a battery, storing energy from sunlight.
2. Cellulose Production:
   • Glucose molecules form cellulose for strengthening cell walls.
3. Starch Formation:
   • Glucose converts into starch for long-term storage.
   • Starch is compact and insoluble, preventing osmotic water intake.
   • Stored starch can be converted back to glucose when needed.
4. Amino Acid & Protein Synthesis:
   • Glucose combines with nitrate ions from soil to form amino acids.
   • Amino acids build proteins.
5. Oils and Fats:
   • Used for energy storage, especially in seeds.

Factors Affecting Photosynthesis Rate

• Light intensity
• Temperature
• Carbon dioxide concentration
• Chlorophyll amount

Additional Resources

• Cognito website offers videos, questions, flashcards, exam questions, and progress tracking.
• Sign up for free at Cognito.org or explore playlists on YouTube.