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.
Many sugar molecules linked together is a polysaccharide. Starch, therefore, is a polysaccharide. Specifically, starch is composed of the sugar glucose. Plants use glucose to produce energy, but they're not always making glucose, just as we're constantly eating to get our energy.