Each pathway generates different waste products. Aerobic respiration proceeds in a series of steps, which also increases efficiency – since glucose is broken down gradually and ATP is produced as needed, less energy is wasted as heat. The simple nature of the final products also indicates anatomy and physiology mckinley pdf download efficiency of this method of respiration. Although there is energy stored in the bonds of these molecules, this energy is not easily accessible by the cell.
All usable energy is efficiently extracted. Generally, in anaerobic respiration sugars are broken down into carbon dioxide and other waste products that are dictated by the oxidant the cell uses. Whereas in aerobic respiration the oxidant is always oxygen, in anaerobic respiration it varies. Each oxidant produces a different waste product, such as nitrite, succinate, sulfide, methane, and acetate. Anaerobic respiration is correspondingly less efficient than aerobic respiration. In the absence of oxygen, not all of the carbon-carbon bonds in glucose can be broken to release energy.
A great deal of extractable energy is left in the waste products. Anaerobic respiration generally occurs in prokaryotes in environments that do not contain oxygen. Fermentation is another process by which cells can extract energy from glucose. It is not a form of cellular respiration, but it does generate ATP, break down glucose, and produce waste products. These varied organic receptors each generate different waste products.