Fat and ATP are different molecules that can both be described as molecules that store energy. Compare the functions of these molecules in terms of energy storage. ATP molecules are made when where there is an excess amount of energy, while fat molecules are used immediately.
ATP molecules are used for long-term storage, while fat is used for immediate energy.
Fat molecules are stable and can be stored for a long time, while ATP is not.
Fat molecules are unstable and can be stored short-term, while ATP molecules are stable and stored long term.