Final answer:
Glycogen is the storage form of carbohydrates in muscle cells and the liver, acting as a significant energy reserve in animals. It is released as glucose through a process called glycogenolysis, which is critical for maintaining energy levels and metabolic balance during fasting or exercise.
Step-by-step explanation:
Glycogen is the storage form of carbohydrates in muscle cells and the liver. This polysaccharide is the animal equivalent of starch and is a highly branched molecule usually stored in liver and muscle cells. When there is a need for energy, or when blood glucose levels decrease, glycogenolysis occurs where glycogen is broken down to release glucose into the bloodstream. This process helps maintain the body's metabolic balance, particularly during fasting or vigorous exercise.
Liver glycogen serves to maintain blood glucose levels for overall bodily function, whereas muscle glycogen provides immediate energy for muscle contraction. Although glycogen does not remain in animal tissues post-slaughter and is thus not a significant component of dietary carbohydrates, it plays a vital role in the human body for energy storage and release, ensuring cells receive glucose during periods of low blood sugar.