ATP

ATP is the acronym for the nucleotide Adenosine Tri-Phosphate. 

ATP consists of:

• A ribose sugar
• Three phosphate groups
• Adenine (a nitrogenous base)

ATP is considered to be a major energy currency of the cell. It is used for all reactions in all cells. 

Properties of ATP:

• ATP is easily soluble
• Easily transported across membranes
• Release energy efficiently
• Only requires one enzyme (ATP synthesise) to hydrolyse it
• Energy is released in small, useable amounts

Uses of ATP:

• Mechanical work (i.e. muscle contraction)
• Active Transport of molecules and ions
• Biosynthesis (building up complex molecules from simple molecules)

How energy is release from ATP?
A single enzyme known as ATP synthase hydrolyses or breaks the bond between the last and middle phosphate group (shown B on the diagram above). This releases energy in useable amounts, so little energy is wasted as heat.

How is ATP generated?
ATP is easily reformed by phosphorylation when a phosphate group is added to ADP (Adenosine Di-Phosphate) by condensation reaction. However, you do not need to many more on ATP. You will learn more about Chemiosmosis in Year 13.