What are the features of ATP which lead it to being termed the 'universal currency' of the cell?

Adenosine triphosphate (ATP for short) is used to provide the energy for many cellular functions - by both animal and plant cells - as cells are unable to source their energy directly from sugars such as glucose. ATP is formed during respiration, when the energy released from ingested glucose powers the addition of a inorganic phosphate molecule to a molecule of adenosine diphosphate (ADP), the enzyme ATP synthase is responsible for this. ATP itself is a small, soluble molecule which can be easily broken down and transported around the cell. The many tasks ATP is used for include the transport work of moving substances, such as ions, across cell membranes in active transport and within the processes of muscular contraction and cellular growth and division too. As well as this, ATP is readily available within cells upon demand as stores are released in manageable amounts, meaning there is no wasted energy. The energy-containing phosphate bond is easily broken down to release the energy it holds and to further this ATP molecules are not lipid soluble and therefore they are unable to pass beyond the cell membrane, ensuring the cell always always has an immediate energy source. Finally, ATP can be deemed a good energy source as it has the ability to transfer a phosphate group, and therefore energy, to other molecules.