How Does a Cell Release Energy From ATP?

Adenosine triphosphate, or ATP, is the energy transfer enzyme of the cell. Adenosine bonds with three phosphate molecules to produce ATP. Adenosine diphosphate, or ADP, is produced from the bonding of two phosphate molecules; adenosine monophosphate, or AMP, results from the bonding of one phosphate molecule. These phosphate bonds require an input of energy to create, and they release energy when broken.

ATP Production

ATP is produced by several different metabolic pathways, each using a different energy source. Most ATP is generated by cellular respiration, which takes place inside the mitochondria. Glucose, the simplest form of sugar, is oxidized and broken down into carbon dioxide and water. The breakdown of one glucose molecule provides enough energy for approximately 30 ADP molecules to be transformed into ATP.

Photosynthesis in plants also produces ATP, using sunlight as the energy source.

Release of energy

ATP is the energy source for most cell metabolic functions. It fuels the active transport of macromolecules across cell membranes, losing one or more phosphates in the process and returning to the lower energy states of AMP or ADP. ATP also provides energy for the synthesis of proteins, DNA, RNA, and other macromolecules.

How Much ATP Is Used?

The average person uses her body weight in ATP every day, even though the average human has only 8.8 oz. of it. This means that each ATP molecule cycles between ADP and ATP 300 times a day.

References

• Biology: Exploring Life; Neil A. Campbell; 2006
• Science Daily: "Nature's Batteries" May Have Helped Power Early Lifeforms
• Clermont College: Cellular Respiration