Photosynthesis

Carbon Dioxide + Water ------- Oxygen + Glucose

6CO₂            +          6H₂O --------   6O₂    +  C₆H₁₂O₆

Plants are producers. They make their own food. Some algae (protists) e.g. seaweed, photosynthesise. Energy from the sun is trapped in the chloroplasts of leaves and is converted into glucose (energy store).

Some glucose (C₆H₁₂O₆) is used to make cellulose for the plant cell walls. 

Some glucose is converted to amino acids (that make up proteins), lipids etc.

Starch is stored as potatoes, veg etc. or it is broken down by the plant for respiration. Starch is a polymer. Glucose is a monomer.

Endothermic: a type of reaction in which energy from the surroundings is transferred to the products e.g. photosynthesis.