Starch is a polysaccharide that is found in plants and is composed of glucose molecules. It serves as an energy reserve for the plant and can be easily broken down into glucose by the enzyme amylase. This allows the plant to quickly access the stored energy when it is needed.
Cellulose is also a polysaccharide that is found in plants, but it is much more difficult to break down into glucose. This is because cellulose is a structural component of plant cell walls, and it is made up of long chains of glucose molecules that are linked together in a different way than those in starch. The bonds between the glucose molecules in cellulose are much stronger, making it more resistant to digestion by enzymes.
The connection is that plants use starch as an energy reserve, whereas cellulose is a structural component that gives plants strength and support.