
ATP and Energy Storage
1. ATP Stores Energy
Living things store energy mainly in the
form of chemical bonds. Within your cells,
energy is constantly moved around from
one large molecule to another. How does
the energy get converted from, say a food
molecule to a muscle molecule? The
answer is adenosine triphosphate, or ATP.
ATP works like a rechargeable battery.
Energy can release by converting ATP to ADP,
which is the “uncharged” form. Likewise, by
binding to a third phosphate group, ADP can
be converted back to ATP, the “charged form.
When you eat lunch, many complex chemical
reactions occur. But in essence al you are
doing is “recharging” your ATP, because in
order to do anything – flexing muscles, thinking, or whatever – your immediate source of energy
is ATP.
2. Energy pathway
At right is a diagram of a major pathway of energy transfer in the body. Large food
Molecules, such as fats, carbohydrates, and proteins are pulled apart to release the energy
in their chemical bonds. This energy is then used in many ways, including the buildup, or synthesis, of other large molecules. Examples of large molecules the body needs to build are proteins that make up much of the body’s structure, and temporary energy storage “banks” like fat and glycogen.

