1 Chemically, ATP is an adenine nucleotide bound to three phosphates. 2  There is a lot of energy stored in the bond between the second and third phosphate groups that can be used to fuel chemical reactions. 3  When a cell needs energy, it breaks this bond to form adenosine diphosphate (ADP) and a free phosphate molecule.
calf muscle pump. calf muscle pump. an action of the calf (soleus) muscles in which the muscles contract and squeeze the popliteal and tibial veins, forcing the blood in those veins to move upward toward the heart. Also called soleus pump.
The pump refers to the heart. It pumps the blood through the  circulatory system to all parts of the body. The circulatory system  includes the arteries and veins which ca â¦ rries the blood around the  body.3 people found this useful.Amber Yetnick.t pumps the blood through the  circulatory system to all parts of the body. The circulatory system  includes the arteries and veins which ca â¦ rries the blood around the  body. 3 people found this useful. Amber Yetnick.