Edexcel iGCSE Biology-2.19 balanced photosynthesis equation- Study Notes- New Syllabus

Photosynthesis Equations

📝 Introduction

Photosynthesis is the process by which green plants, algae, and some bacteria make food using light energy.
Chlorophyll in chloroplasts absorbs light energy and converts it into chemical energy stored in glucose.
Oxygen is released as a useful by-product.

📖 Word Equation

\[
6CO_{2} + 6H_{2}O \;\rightarrow\; C_{6}H_{12}O_{6} + 6O_{2}
\]

(light energy + chlorophyll)

🔬 Balanced Chemical Symbol Equation

\[
\text{Carbon dioxide} + \text{Water} \;\rightarrow\; \text{Glucose} + \text{Oxygen}
\]

(light energy + chlorophyll)

🧠 How to Remember the Balanced Equation

• 6 molecules CO₂ + 6 molecules H₂O needed.
• Makes 1 molecule glucose (C₆H₁₂O₆).
• Produces 6 molecules O₂.

👉 Trick: Think 6-6-1-6 (left to right).

🌟 Importance of the Equation

• Shows that light energy is converted to chemical energy.
• Explains why plants need CO₂ and H₂O to grow.
• Reminds that photosynthesis also produces oxygen, essential for respiration.

📊 Summary Table

⚡ Quick Recap
Word equation: CO₂ + H₂O → Glucose + O₂.
Symbol equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
Energy source: light, captured by chlorophyll.
Mnemonic: “6-6-1-6” (6 CO₂ + 6 H₂O → 1 glucose + 6 O₂).