The process of photosynthesis is divided into phases:
(a) Light dependent reactions: In this phase energy from sunlight is used by chlorophyll molecules to form ATP and NADPH.
(b) Dark reaction: In this phase, ATP and NADPH formed in light reactions is used to fix carbon dioxide into carbohydrates. This phase has three stages: carboxylation, glycolytic reversal and rengeneration. The reactions in this phase do not depend on light.