Does it accumulate in animal cells as the main energetic substance?

Animals accumulate glycogen in cells. It serves as a source of energy. It is a carbohydrate that has a rather complex structure. Its chemical formula is C6H10O5. These molecules are formed by the breakdown of glucose in the body under the action of special digestive enzymes. This breakdown begins in the mouth, as saliva has digestive enzymes that break down carbohydrates. Further, in the stomach, these processes continue. Energy is accumulated in cells so that in the event of a lack of food, we have a reserve supply.