In Photosynthesis, What Are the Reactants and the Products of the Light Reactions? Where Do the Dark Reactions Occur? What Are the Reactants and Products of the Dark Reactions?

Photosynthesis is a fascinating process that plants, algae, and some bacteria use to convert light energy into chemical energy. It occurs mainly in two stages: the light reactions and the dark reactions (Calvin cycle).

Light Reactions

The reactants of the light reactions are water (H₂O) and sunlight. During this stage, light energy is captured by chlorophyll and other pigments in the thylakoid membranes of chloroplasts. This energy splits water molecules into oxygen, protons, and electrons.

The main products of the light reactions are oxygen (O₂

Dark Reactions (Calvin Cycle)

The dark reactions, also known as the Calvin cycle, take place in the stroma of chloroplasts, a fluid-filled space surrounding the thylakoids. These reactions do not require light directly but utilize the products generated from the light reactions.

The reactants for the dark reactions are carbon dioxide (CO₂

The main product of the dark reactions is glucose (C₆H₁₂O₆), which serves as an energy source for the plant. The cycle also generates ADP and NADP⁺, which are recycled back to the light reactions.

In summary, the light reactions produce oxygen, ATP, and NADPH using water and sunlight, while the dark reactions occur in the stroma, using ATP, NADPH, and carbon dioxide to produce glucose.