ATP Flashcards
What is ATP?
- Universal energy currency
Universal = Used in all organisms
Currency = Can be used for different reactions and is reused countless times - Energy within organic molecules eg glucose can be transferred into numerous molecules of ATP via respiration
(like breaking £10 note into pound coins)
Uses of ATP as an energy currency benefits:
- The hydrolysis of ATP can be carried out quickly and easily by the enzyme ATP hydrolase
- A useful quantity of energy is released from the hydrolysis of one ATP molecule
• this is beneficial as it reduces waste
• also gives the cell control over what processes occur
Roles of ATP : Good energy donor
- Good energy donor because of the instability of its phosphate bonds and their tendency to **hydrolyse with ease*
HOWEVER : this also means that its poor as a long term energy store - This means its used as an immediate energy source by cells
Roles of ATP : Energy quantities
Manageable energy quantities : They released less energy than a glucose molecule
Quick releases of energy : Hydrolysis of ATP to release energy is a single short reaction
Key uses of ATP in cells
Metabolic processes
Metabolic processes : Building up larger macromolecules from smaller molecules
eg forming starch from glucose or polypeptides from amino acids
Key uses of ATP in cells
Movement
Movement : Muscle contraction requires ATP to facilitate the sliding of filaments
Key uses of ATP in cells
Active Transport
Energy used to change the shape of carrier proteins to enable them to pump ions of molecules against the concentration gradient
Key uses of ATP in cells
Activation of molecules
The phosphate released from ATP can be used to phosphorylate other molecules
This makes them less stable by lowering the activation energy and makes them more reactive
Structure of ATP
ATP is a phosphorylated macromolecule
It has 3 key parts :
Adenine
Ribose - Sugar containing a 5 carbon ring structure (pentose sugar)
Phosphates - A chain of 3 phosphates (triphosphate)
The combination of adenine with ribose creates adenosine
How many phosphates can attach to adenosine
Between 1-3
1 Phosphate - Adenosine Monophosphate (AMP)
2 Phosphates - Adenosine Diphosphate (ADP)
3 Phosphates- Adenosine Triphosphate (ATP)
What is phosphorylation?
Phosphorylation = Adding phosphate
- It requires energy to form the bond ( condensation reaction)
- This energy is stored within the bond
How does phosphorylation make molecules less stable?
Tends to make molecules less stable and more reactive
- When the bond is broke (hydrolysed) and the phosphate is lost the stored energy is released
The bond has a low activation energy so is easily hydrolysed
What is ATP hydrolysis?
Hydrolysis of ATP to adenosine diphosphate (ADP) and an inorganic phosphate group (Pi) is catalysed by the enzyme ATP hydrolase
ATP hydrolysis
ATP ——————> ADP + Pi
ATP hydrolase
ATP is used for all’s cellular processes requiring energy
The inorganic phosphate (Pi) released can be used for other compounds
What is ATP re synthesis ?
Organisms cannot build up large stores of ATP and it rarely passes through the cell surface membrane
- So cells must make ATP when they need it
- ADP + Pi —> ATP
ATP formed from ADP and Pi by the enzyme ATP synthase
ATP synthesis is a condensation reaction as water is realised as a waste product
