Starch is the substrate and maltose is the product

Prof. Wilson: Excellent, well-done! Amylase is an important enzyme that is found in the saliva and the small intestine and breaks down starch, a polysaccharide, into maltose, a disaccharide. Why is that important in digestion?

You: Big molecules cannot cross plasma membranes, which is important for absorption into the bloodstream and used as energy sources by the body. Without amylase the reaction would be very slow and thus this enzyme is vital for efficient carbohydrate digestion and energy metabolism. 

Prof. Wilson: Great, it seems we are ready to start our experiment now.