Difference between starch and cellulose
Answers
Starch and cellulose are two very similar polymers. In fact, they are both made from the same monomer, glucose, and have the same glucose-based repeat units.
There is only one difference. In starch, all the glucose repeat units are oriented in the same direction. But in cellulose, each succesive glucose unit is rotated 180 degrees around the axis of the polymer backbone chain, relative to the last repeat unit.
When bigshot scientists are talking bigshot scientist talk they say that the glucose units in starch are connected by alpha linkages, and that the glucose units in cellulose are connected by beta linkages.
Does this make any difference? It makes a lot of difference! The most important difference in the way the two polymers behave is this: You can eat starch, but you can't digest cellulose. Your body contains enzymes that will break starch down into glucose to fuel your body. But we humans don't have enzymes that can break down cellulose. Some animals do, like termites, who eat wood, or cattle, who eat grass, and break down cellulose in their four-chambered stomachs. So unless you're a termite or a cow, don't try to nourish yourself on woodchips.