One tablespoon of standard sucrose, or table sugar, contains approximately 48 calories and about 12 grams of sugar.
Starch is a polymer of the monosaccharide glucose: Starch is the principal polysaccharide used by plants to store glucose for later use as energy. Plants often store starch in seeds or other specialized organs; for example, common sources of starch include rice, beans, wheat, corn, potatoes, and so on.
Specifically, starch is composed of the sugar glucose. Glucose is a sugar molecule made up of carbon (C), hydrogen (H), and oxygen (O) with a basic chemical formula of C6H12O6. Plants use glucose to produce energy, but they're not always making glucose. Much like we store up energy reserves after eating, so do plants.