In what form is energy primarily stored in animal tissues?

Energy in animal tissues is primarily stored as glycogen and triglycerides. Glycogen serves as a key energy reserve in animals, particularly in the liver and muscle tissues. It is a polysaccharide composed of glucose units, allowing for rapid mobilization of glucose when energy is needed. Triglycerides, on the other hand, are a form of fat, consisting of glycerol and fatty acids, and serve as a significant source of long-term energy storage. They provide more energy per gram than carbohydrates due to their higher energy density, making them an essential component of energy storage in the body.

Other forms of potential energy, like glucose itself, are typically not stored directly in large amounts but rather utilized for energy production when needed. Proteins primarily serve structural and functional roles rather than being a significant energy store; while they can be metabolized for energy in times of need, they are not a primary energy storage form. ATP acts as an immediate energy currency within cells rather than as a long-term storage form of energy. Thus, glycogen and triglycerides are the primary means through which animals store energy in their tissues.