Plants convert sunlight into energy through a process called photosynthesis , which turns light energy into chemical energy stored in sugar (glucose).

In one sentence

Plants use sunlight, water, and carbon dioxide in their leaves to make glucose and oxygen inside special cell parts called chloroplasts.

Step‑by‑step: how it works

  1. Light is captured
    • Photosynthesis happens mainly in the leaves, in tiny structures called chloroplasts that contain green chlorophyll.
 * Chlorophyll absorbs light energy from the sun, especially in the blue and red parts of the spectrum.
  1. Water and carbon dioxide are taken in
    • Roots absorb water from the soil and transport it up the stem to the leaves.
 * Tiny pores on the underside of leaves, called stomata, open to let carbon dioxide from the air enter the leaf.
  1. Light-dependent reactions (energy capture)
    • In the thylakoid membranes inside chloroplasts, light energy excites chlorophyll molecules and is used to split water into oxygen, protons, and electrons.
 * Oxygen is released as a gas, while the reactions produce two key energy molecules: ATP and NADPH, which store captured light energy.
  1. Calvin cycle (sugar building)
    • In the stroma (the fluid space inside the chloroplast), the plant uses ATP and NADPH to power a series of reactions called the Calvin cycle.
 * An enzyme called rubisco helps attach carbon dioxide to a 5‑carbon molecule, ultimately producing 3‑carbon molecules that are rearranged to form glucose.
  1. Energy storage and use
    • The glucose made can be used right away in respiration for energy, or turned into starch, oils, or other substances for storage and growth.
 * This stored chemical energy is what fuels the plant’s activities and forms the base of most food chains on Earth.

The overall equation

You can summarize photosynthesis with this word equation (simplified):

carbon dioxide + water + light energy → glucose + oxygen

This is the core process by which plants convert sunlight into usable energy for themselves and, indirectly, for almost all other life.

TL;DR: Photosynthesis is a two‑stage process in chloroplasts where light energy first makes ATP and NADPH, then these are used to turn carbon dioxide and water into energy‑rich glucose, releasing oxygen as a by‑product.