Final answer:
The cells with the highest concentrations of glycogen are hepatocytes (liver cells) and muscle cells. Hepatocytes store glycogen for regulation of blood glucose levels, while muscle cells use it for energy during exercise. Both cell types synthesize glycogen from excess glucose in the absorptive state. Option d is correct..
Step-by-step explanation:
The cells with the highest concentrations of glycogen are hepatocytes, which are liver cells, and muscle cells. Glycogen is an energy reserve carbohydrate that is particularly abundant in these two cell types. In hepatocytes, glycogen can constitute 4% to 8% by weight of the liver tissue, and it functions to maintain blood glucose levels, providing glucose to other cells as needed. In muscle cells, which store about 70% of the body's total glycogen, it serves as an immediate energy source during vigorous exercise by being broken down to glucose for glycolysis right in the muscle itself.
The liver's high concentration of glycogen makes sense given its central role in regulating metabolism and blood glucose levels. Muscle cells, on the other hand, need glycogen stores to readily supply energy during periods of high demand. Both liver and muscle cells are equipped for glycogen synthesis during the absorptive state, where they convert excess glucose to glycogen via glucose-6-phosphate. This stored glycogen can then be used as fuel during fasting or vigorous activity.