How is starch made in a plant?

Starch is a branching polypeptide. Individual glucose molecules are attached to each other through a series of enzymatic reactions (using an ATP as fuel). These bonds (as opposed to the ones in cellulose) are easy to break, providing readily accessible energy. Many staple crops, such as potatoes, contain large amounts of starches. Plants will form glucose in the leaves from photosynthesis, providing a high concentration of glucose, forcing some down into the roots. When the plant is storing energy, it will convert glucose in the roots into starch, allowing for the glucose to continue flowing into the roots to be stored. When the plant needs that energy (say in the Spring) it will break down the starch in the roots, creating a high concentration of glucose, forcing it up into the leaves to rebuild and fuel.

cassava starch processing flow chart