Photosynthesis in Plants

  • Photosynthesis Overview

    • Process used by plants to create food.

    • Involves light energy (D Greek: 'photo' = light, 'synthesis' = putting together).

  • Raw Materials

    • Carbon Dioxide (CO2) and Water (H2O) are essential for photosynthesis.

    • Energy from sunlight is required for the reaction.

  • Location and Mechanism

    • Photosynthesis occurs in chloroplasts within plant cells.

    • Chlorophyll (green pigment) absorbs sunlight.

  • Photosynthesis Reaction

    • Chemical equation: 6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂

    • Products: Glucose (used for energy and growth) and Oxygen (released as byproduct).

  • Factors Affecting Rate of Photosynthesis

    • Light Intensity: More light increases photosynthesis rate until saturation.

    • Carbon Dioxide Concentration: Higher concentrations increase the rate (e.g., in greenhouses).

    • Temperature: Optimal range for enzyme activity; too high can denature enzymes.

  • Uses of Glucose

    • Energy source for cellular respiration.

    • Stored as starch for later use.

    • Used to synthesize other organic substances (proteins, fats).

    • Converted to sucrose for transport.

  • Testing for Starch

    • Use iodine solution: blue-black indicates starch presence.

    • Procedure: Boil leaf, treat with alcohol to remove chlorophyll, then stain with iodine.