The energy for photosynthesis comes from light, usually sunlight, which plants capture and convert into chemical energy stored in sugars like glucose.

Core idea

  • Photosynthesis is the process where plants, algae, and some bacteria use light energy to turn carbon dioxide and water into glucose and oxygen.
  • The light energy is absorbed mainly by a green pigment called chlorophyll in the chloroplasts of plant cells.

In simple terms

You can think of photosynthesis as plants “charging their batteries” using light:

  • Light energy → turned into chemical energy (in molecules like ATP and NADPH first, then in glucose).
  • That chemical energy is what the plant uses later for growth, repair, and other life processes (and it also supports almost all food chains on Earth).

A bit more detail

  • During the light-dependent reactions , energy from light is captured and used to make high‑energy molecules (ATP and NADPH) and to split water, releasing oxygen.
  • In the Calvin cycle (light‑independent reactions), the energy in ATP and NADPH is used to build glucose from carbon dioxide.

How much energy?

  • Producing one mole of oxygen and associated glucose stores roughly 117 kilocalories of chemical energy.
  • Under ideal conditions, plants can theoretically convert about 26% of the incoming light energy they use into stored chemical energy, though real-world efficiency is usually lower.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.