The photosynthesis reaction

Plant structures and their functions · Photosynthesis and limiting factors · note 2 of 6

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The photosynthesis reactionSpec 6.2

Photosynthesis in plants and algae is an endothermic reaction. This means it takes in energy from the surroundings. The energy comes from light, which is absorbed by the green pigment chlorophyll in the chloroplasts.

The light energy is used to react carbon dioxide and water to produce glucose and oxygen.

carbon dioxide + water → glucose + oxygen (in the presence of light)

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Where the raw materials come from and where the products go
Substance	Reactant or product	Source or fate
Carbon dioxide	Reactant	Diffuses into the leaf from the air
Water	Reactant	Absorbed from the soil by the roots and carried to the leaf in the xylem
Glucose	Product	Used for respiration, or to build new plant material (biomass)
Oxygen	Product	Diffuses out of the leaf into the air

A plant cell with chloroplasts; light energy, carbon dioxide from the air and water from the roots go in, and oxygen and glucose come out, above the word equation carbon dioxide plus water gives glucose plus oxygen. — Photosynthesis in a leaf cell: **light energy** is absorbed by chlorophyll in the chloroplasts.