The glucose made in photosynthesis is a store of chemical energy and a building material. Plants use some of it straight away for respiration, which transfers the energy the plant needs for its life processes.
Glucose can be converted into insoluble starch for storage. Starch is insoluble, so it does not affect the water balance of cells by osmosis, which makes it a good store. Glucose can also be used to make fat or oil for storage, for example in seeds. It can be used to make cellulose, which strengthens the cell wall.
Glucose can also be used to make amino acids for protein synthesis. To do this the plant also needs nitrate ions, which are absorbed from the soil.