ATP is like a charged battery
ADP is like a partially charged battery that will produce a dim light & ATP is like a fully charged battery that produces a bright light
adp+p(i)--->atp ADP +P ---> ATP
ADP is like a partially charged battery because there is still energy contained within the bond between the first and second phosphate groups. However, it lacks the "high energy" bond that exists between the second and third phosphate groups in ATP.
Because ATP stores energy and releases it turning into ADP in the process. This ADP is then converted back to ATP by the cells so that its energy is ready when required, just like a rechargeable battery.
ATP (with 3 Phosphate Groups) would be the full charged battery. ADP (with 2 Phosphate Groups) would be the partially charged battery. To release energy, the bond between the 2nd and 3rd phosphate group is released. To store energy, a bond is made between the 2nd and 3rd phosphate group.
When ATP is used, it becomes ADP or Adenine Di-Phosphate. Adding another phosphate will "recharge" ATP.
ATP is an energy and molecule it powers all of the cells energy needs somewhat like a battery. ATP is generated when a phosphate (P) group is added to one ADP.
adp+p(i)--->atp ADP +P ---> ATP
ATP has three phosphate groups attached to the nucleic acid adenosine. The last or third bond has the most energy in it and when it is broken. that energy is used to drive cell activities. It may be helpful to think of ATP as a battery that gets charged, and as soon as it is charged, it can off a spark of energy that can be used to do work in the body.
Phosphorylation is the addition of a phosphate to ADP to form ATP. ADP + P = ATP Dephosphorylation is the removal of a phosphate from ATP to form ADP. ATP - P = ADP
ATP (with 3 Phosphate Groups) would be the full charged battery. ADP (with 2 Phosphate Groups) would be the partially charged battery. To release energy, the bond between the 2nd and 3rd phosphate group is released. To store energy, a bond is made between the 2nd and 3rd phosphate group.
Think of ATP (and ADP) as a battery ... storing energy to be used as needed.