<P> Digestion' is the breakdown of carbohydrates to yield an energy rich compound called ATP . The production of ATP is achieved through the oxidation of glucose molecules . In oxidation, the electrons are stripped from a glucose molecule to reduce NAD+ and FAD . NAD+ and FAD possess a high energy potential to drive the production of ATP in the electron transport chain . ATP production occurs in the mitochondria of the cell . There are two methods of producing ATP: aerobic and anaerobic . In aerobic respiration, oxygen is required . Oxygen plays a key role as it increases ATP production from 4 ATP molecules to about 30 ATP molecules . In anaerobic respiration, oxygen is not required . When oxygen is absent, the generation of ATP continues through fermentation. There are two types of fermentation: alcohol fermentation and lactic acid fermentation . </P> <P> There are several different types of carbohydrates: polysaccharides (e.g., starch, amylopectin, glycogen, cellulose), monosaccharides (e.g., glucose, galactose, fructose, ribose) and the disaccharides (e.g., sucrose, maltose, lactose). </P>

Where does the initial breakdown of glucose occur