Biology Chapters

1. Introduction2. Classification of Organism3. Cytology4. Genetics5. Organic Evolution6. Classification of Plant Kingdom7. Plant Morphology8. Plant Tissue9. Photo-synthesis10. Plant Hormones11. Plant Diseases12. Ecology13. Pollution14. Classification of Animal Kingdom15. Animal Tissue16. Human Blood17. System of Human Body18. Nutrients19. Human Diseases20. Miscellaneous

Photosynthesis

“Photosynthesis is the process by which green plants make their own food using sunlight.”

What is Photosynthesis?

Photosynthesis is the process through which green plants, algae, and some bacteria synthesize glucose (a type of sugar) from carbon dioxide and water using sunlight. It is a fundamental biological process that sustains life on Earth by producing oxygen as a byproduct.

Chemical Equation of Photosynthesis

6CO2 + 6H2O     C6H12O6 + 6O2

In the presence of sunlight and chlorophyll

Steps of Photosynthesis

  • Absorption of Light: Chlorophyll absorbs sunlight energy.
  • Photolysis of Water: Water is split into oxygen, protons, and electrons using light energy.
  • Carbon Fixation: CO₂ is converted into glucose through a series of biochemical reactions (Calvin Cycle).

Diagram of Photosynthesis

You can place a labeled diagram of photosynthesis here (e.g., image of chloroplast or leaf cross-section).

Factors Affecting Photosynthesis

  • Light Intensity: More light increases the rate up to a certain limit.
  • Carbon Dioxide Concentration: Affects the rate of carbon fixation.
  • Temperature: Enzyme-controlled reactions have an optimum temperature range.
  • Water Availability: Essential for photolysis and turgidity of cells.

Importance of Photosynthesis

  • Provides food to all living organisms directly or indirectly.
  • Releases oxygen necessary for respiration.
  • Reduces carbon dioxide from the atmosphere.
  • Maintains the balance of gases in the environment.

Previous Year Questions

  • SSC JE 2021: Which gas is released during photosynthesis?
    • Option A: Carbon dioxide
    • Option B: Oxygen
    • Option C: Nitrogen
    • Option D: Hydrogen

    Correct Answer: B. Oxygen

  • HSSC CET 2022: What is the role of chlorophyll in photosynthesis?
    • Option A: Absorption of CO₂
    • Option B: Conversion of glucose
    • Option C: Absorption of light energy
    • Option D: Release of water

    Correct Answer: C. Absorption of light energy

  • RRB JE 2019: Photosynthesis occurs in which part of the plant cell?
    • Option A: Mitochondria
    • Option B: Nucleus
    • Option C: Chloroplast
    • Option D: Ribosome

    Correct Answer: C. Chloroplast

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