ATP Flashcards
What does ATP stand for?
Adenosine Triphosphate.
What type of molecule is ATP?
A phosphorylated macromolecule
What 3 parts is ATP made up of?
Adenine - nitrogen containing organic base
Ribose - 5-carbon ring structure that acts as backbone
Phosphates - a chain of 3 phosphates
Is adenosine Triphosphate a nucleotide?
Yes
What feature of the ATP gives it its ability to storing energy?
The 3 phosphate groups
Why do the bonds between the phosphate groups have a low activation energy - and so easily broken?
They are unstable
What happens when the bonds between the phosphate groups break?
Considerable amounts of energy are released.
In living cells, which phosphate is removed?
The terminal one.
What is the equation for the hydrolysis of ATP?
ATP + Water —> ADP + Pi + Energy
What is ADP?
Adenosine diphosphate
What does Pi stand for?
An inorganic phosphate (removed from the 3 groups)
What enzyme catalyses the hydrolysis of ATP?
ATP hydrolase
Is the conversion of ATP to ADP a reversible reaction?
Yes
How does the nature of the reaction for the hydrolysis of ATP mean it can be reformed?
Reversible - so Pi can be added to ADP to reform ATP (the reverse of the equation)
What enzyme catalyses the reformation of ATP?
ATP synthase
What type of reaction is the formation of ATP?
Condensation
What is phosphorylation?
The addition of a phosphate Molecule (to ADP)
What 3 ways does phosphorylation occur?
-Photophosphorylation
-Oxidative phosphorylation
-Substrate level phosphorylation
Where does photophosphorylation occur?
In chlorophyll-containing plant cells during photosynthesis
Where does oxidative phosphorylation occur?
In plant and animal cells during respiration
Where does substrate level phosphorylation occur?
In plant and animal cells when phosphate groups are transferred from donor molecules to ADP
Why is ATP an immediate energy source and not a long term energy store?
Very unstable bonds - fats and carbohydrates are used instead
How come cells do not store large quantities of ATP?
ATP is rapidly reformed from ADP and Pi, so a few seconds’ supply supplies a lot more
Why is glucose not an ideal energy source for immediate supply?
-less energy released from ATP so is more manageable quantity than glucose
-hydrolysis of ATP is a single reaction whereas breakdown of glucose is a series of reactions so takes longer
Why does ATP need to be continuously made within the mitochondria of the cells that need it?
It cannot be stored
What two types of cells possess many mitochondria and why?
Muscle and epithelial cells - require energy for movement and active transport respectively
How is ATP used for metabolic processes?
Provides the energy needed to build up macromolecules from their basic units (E.G. making starch from glucose)
How is ATP used for movement?
Provides the energy for muscle contraction - in particular for the filaments of the muscle to slide past one another and therefore overall shorten the muscle fibre.
How is ATP used for active transport?
Provides the energy to change the shape of carrier proteins in plasma membranes - allows ions/molecules to be moved against a concentration gradient.
How does ATP help with secretion?
It is needed to form the lysosomes necessary for the secretion of cell products.
How is ATP used for the activation of molecules?
The Pi which is released during hydrolysis can be used to phosphorylate other compounds in order to make them more reactive and lowering the activation energy in enzyme - catalysed reactions.
What is an example of adding Pi to a molecule to make it more reactive?
Addition Pi to glucose molecules at the start of glycolysis
