Final answer:
The cells with the highest concentration of glycogen are hepatocytes and muscle cells. Hepatocytes store and regulate blood glucose, while muscle cells store the majority of the body's glycogen for energy during exercise.
Step-by-step explanation:
The cells with the highest concentrations of glycogen are hepatocytes (liver cells) and muscle cells. Glycogen is the primary energy reserve carbohydrate in animals and is especially abundant in these cells. Hepatocytes store glycogen and release glucose into the blood to maintain normal glucose levels. During the absorptive state, they convert excess glucose to glycogen for storage via glucose-6-phosphate. Muscle cells, on the other hand, store around 70% of the body's glycogen. Though they contain a lower percentage by weight compared to the liver, the overall muscle mass in the body results in a higher total storage of glycogen.
Glycogen metabolism includes processes like glycogenesis, where glucose is converted into glycogen, and glycogenolysis, where glycogen is broken down into glucose. The stored glycogen in muscle cells is a readily available source of glucose during vigorous exercise for glycolysis within the muscle itself.