Answer:
The hydrolysis of ATP to ADP is exothermic
The hydrolysis of ADP to ATP is endothermic
Explanation:
This is the reaction that can explain what happens in the hydrolisis of ATP and ADP:
ATP + H2O ⇋ ADP + Pi + energy
As we can see in the reaction to produce energy we need water (that's why it's so important to drink a lot of water) and ATP, the ATP is also called the energy molecule because when she gives one phosphate group she frees energy to the medium.
Conversely to add one phosphate to the ADP we need energy to bind it and creat an ATP molecule, in this process water is liberated.
In other words, the ATP hydrolysis liberates energy so it's exothermic. And the ADP hydrolysis needs energy for that reason it's endothermic.
