Photosynthesis is the process by which plants make carbohydrates from raw materials, using energy from light. During photosynthesis:

  • light energy is absorbed by chlorophyll - a green substance found in chloroplasts in green plant cells and algae
  • absorbed light energy is used to convert carbon dioxide (from the air) and water (from the soil) into a sugar called glucose
  • oxygen is released as a by-product

The following equations summarise what happens in photosynthesis:

\[carbon\:dioxide + water \xrightarrow[chlorophyll]{light} glucose + oxygen\]

\[6CO_{2}+6H_{2}O\xrightarrow[chlorophyll]{light} C_{6}H_{12}O_{6}+ 6O_{2}\]

Some glucose is used for respiration, while some is converted into insoluble starch for storage. The stored starch can later be turned back into glucose and used in respiration.