Organic Compounds - ATP
- Adenosine triphosphate (ATP) is used throughout the cell.
- ATP provides energy for the cell to do work.
- mechanical work - move cilia, vesicles, etc.
- transport work - across the membrane(s).
- chemical work - force non-spontaneous reactions.
- ATP is composed of phosphate groups, a ribose and adenine.
- Adenosine monophosphate (AMP) is a monomer of RNA.
- Adding additional phosphate groups yields an unstable molecule.
- Negatively charged phosphates repel one another.
- The bond is easily broken by hydrolysis.
- ATP + H2O ADP + PO4-
- Energy yield is approximately -10 kcal/ mol
- ATP usually gives the PO4- to another molecule.
- The new molecule is said to be phosphorylated.
- That new molecule is even more unstable and quickly does "something".
- a motor protein moves.
- a membrane protein transports a solute.
- a different chemical reaction proceeds.
- The ATP becomes ADP. ADP is more stable.
- ADP is phosphorylated to become ATP, completing the cycle.
- In one minute a working muscle cell uses 10,000,000 ATP molecules.
- That is the cell's entire supply, so ADP must be recycled into ATP.
- Even resting in bed, you use 20 kg of ATP every 24 hours!