the nitrogenous purine: adenine,
a ribose sugar and
three phosphate groups linked
by what are known as phosphoanhydride bonds.
The terminal two phosphoanhydride bonds, indicated
in the red, are known as high energy bonds because when they are broken
a tremendous amount of free energy is released.
This released free energy can be used to do biological
work such as drive biochemical reactions like active transport, muscle
contraction, cell movement, movement of intracelluar organelles and chromosomes.
Thus, when in ATP, the phosphoanhydride bonds represent energy that has the potential to do biochemical work.
Return to covalent bonds