Question

5 Cellular ATP concentrations are maintained well above equilibrium concentrations in cells. Explain how high cellular ATP concentration relates to actual free energy changes (AG) for ATP hydrolysis relative to the standard free energy change (AG)

Answer 1

Upon hydrolysis of ATP is produces ADP and energy released due to breaking of one phosphide linkage.

ATP is called stove of energy. Frenzy stoled in phosphide linkages. upon Hydrolysis of ATP 97 Releases end 9nd get converted to ADP. Fuilibrium is Represented as - ATP + 90 ² ADP + Pi - The equillibrium constant Reg for equation is Proportional to Product concentration and inversely propolhonad to Rosciant ATP concentration Kee [ADP] [Pi] Bet concentration [47P] [HO] 4 [H0] = 1 always Key = [AD P7 [Pi] © . [ATP] we 4lso know the Relation for free energy and Reaction Rate constant at equilibrium conditions 1 AG = -RT en Keg - 3 - R is gas constant, aG is change in free Energy, T-temp. from Equation ② and ③ we get Relation Between of and ATP concentration. 20=-RT ens [ADP] [Pi] 2 - AG= - RT en T41P] } Equation Lower says hertence the CATP] concentration, - the oa will be more negative and Reaction will be more spontaneous. Le FOR Better sponteinity of Reaction, Lower wo should be - concentration of ATP.” High ATP concentration Makes AG Free energy Less Reaction less spontaneous » - Negative that means maker ce ATP concentrato increases AG D resses sa changes from more Negative to Less Negative

we know the equilibrium constant and free energy are related with a formula, and also more the equilibrium constant more negative the free energy and more spontaneous the reaction will be.

but equilibrium constant is inversely proportional to [ATP] concentration.

hence for High ATP concentration , free energy will increases from more negative to less negative value.