Digestive System 2. Absorption - Passage of nutrients through the wall of the intestine and eventually, into the blood stream. A unit of energy. A. Carbohydrates - Supplied mostly by plants. Simple sugar, glucose, is the most important monsaccharide in the body.
All cells use glucose for energy.
Except for tooth decay not really associated with disease. Starches - It is a complex carbohydrate consisting of long chains of glucose molecules. Plants are the source of fiber. Add bulk to stool and decreases time for stool to move through digestive track. Calories - Each gram of carbohydrate contains 4 calories.