What is the most important and main compound cells use to store and release energy

ATP (Adenosine triphosphate)

Explanation:

ATP that is also known as energy currency of the cell is the principal compound which living organisms use to release and store chemical energy. This is because the structure of this molecule which has the ability to store and release enormous amount of energy.

As you can see in the structure of ATP molecule, it consists of one sugar unit ribose, bonded with an adenosie unit at one side and three phosphate atoms at the other side. The phosphate bonds hold tremendous importance for making ATP an energy currency.

The process of release of energy involve the breakdown of phosphate bonds from ATP molecule and is known as hydolysis. The first phosphate bond breakage produces 7 kcal/mole amount of energy while the other ones produce relatively lesser amount of energy as depicted in figure.

When the cell needs energy to perform its activities one phosphate bond is broken from ATP releasing energy stored in the bond that the cell can use to do work and converts ATP to ADP (Adenosine di phosphate).

When cell needs to store energy a phosphate bond is added with ADP and energy is again stored. This is a part of the process of cellular respiration that is key process of producing energy.

Hope it help!

not always but somethings can be reproduced in a laboratory.