Which carbohydrate source is used by anaerobic lactic metabolism to produce energy?

Glycogen is the correct answer because it is the stored form of glucose in animals and serves as a key energy source during anaerobic lactic metabolism. This type of metabolism occurs when oxygen is limited, such as during high-intensity exercise, and relies on the rapid breakdown of glycogen into glucose, which is then converted into energy.

In this process, glycogen is converted to glucose-6-phosphate and then metabolized to produce ATP (adenosine triphosphate), the energy currency of cells. Since oxygen is not available in significant amounts, pyruvate, a byproduct of glucose breakdown, is converted to lactate instead of entering aerobic metabolism. This mechanism allows the body to quickly generate energy for short bursts of activity.

In contrast, fats are oxidized primarily during aerobic metabolism and are not a direct source for anaerobic processes. Proteins can be used for energy but are typically utilized when carbohydrate stores are low and not preferred for quick energy needs. Starch, while a carbohydrate source, must be broken down into glucose before it can be used for energy and is less relevant to anaerobic metabolism compared to glycogen, which is readily available for immediate use in muscle cells.