Which process do plants use to convert light energy into chemical energy?

• A. Respiration
• B. Transpiration
• C. Photosynthesis
• D. Fermentation

Answer: (C)

Plants convert light energy into chemical energy through photosynthesis. In the chloroplasts, light-absorbing pigments like chlorophyll capture photons and drive reactions that start by splitting water to release oxygen and generate energy carriers, ATP and NADPH. Those carriers power the next stage, where carbon dioxide is fixed into sugars during the Calvin cycle. The sugars store chemical energy that the plant can later use for growth and metabolism.

Other processes don’t turn light into stored chemical energy in the same way. Respiration uses stored sugars to release energy for cellular work and doesn’t rely on light energy. Transpiration is simply water loss through leaves and isn’t about energy conversion. Fermentation can generate ATP without oxygen, but it doesn’t convert light energy into chemical energy to build sugars.