in order to make proteins from glucose, what other substance do plant cells need?

To make proteins from glucose, plant cells need another essential substance: nitrates. Nitrates provide the nitrogen required to produce amino acids, which are the building blocks of proteins. While glucose supplies carbon, hydrogen, and oxygen, nitrates from the soil supply nitrogen, allowing the plant to synthesize amino acids and subsequently proteins. Hence, plant cells combine glucose with nitrates absorbed from the soil in order to make amino acids, which are then assembled into proteins.