Conversion of atmosphere carbon into chemical bond energy occurs during the process of?

Analyze the question The question asks which process takes carbon from the atmosphere (as carbon dioxide) and converts it into chemical bond energy, meaning energy stored in organic molecules such as glucose.

Explain the concept Plants, algae and some bacteria take in carbon dioxide from the air. Using light energy trapped by chlorophyll, they build it into carbohydrates. This is carbon fixation, and it happens in photosynthesis.

Equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (in the presence of light and chlorophyll)

Light energy is converted into chemical energy stored in the bonds of glucose. The carbon from atmospheric CO₂ becomes part of that glucose molecule.

Check each option

• A. Transpiration: This is loss of water vapour from leaves. It has nothing to do with carbon or energy storage.
• B. Photosynthesis: CO₂ from the air is fixed into glucose, and the energy is stored in chemical bonds. This fits.
• C. Digestion: This breaks down large food molecules into smaller soluble ones. It does not involve atmospheric carbon.
• D. Respiration: This does the reverse. It breaks down glucose to release energy and gives out CO₂ into the atmosphere.

Answer The correct option is B. photosynthesis.

Exam tip Remember the opposites:

• Photosynthesis stores energy and takes in CO₂.
• Respiration releases energy and gives out CO₂.

If a question mentions "atmospheric carbon" being "fixed" or "converted into chemical energy", think photosynthesis.