Thermodynamics Flashcards
(38 cards)
What is the condition for a reaction to be thermodynamically feasible?
Delta G has to be less than 0
What does delta G equate to in a system?
The maximum amount of useful work that can be done by the system
What defines an enthalpically driven reaction?
Delta S < 0
What defines an entropically driven reaction?
Driven by free energy difference (delta G) between reactants and products
What occurs when delta G = 0?
The reaction proceeds until delta G = 0
How is delta G related to the concentrations of reactants?
Delta G is calculated using concentrations of reactants
What is the typical concentration of ATP in cells?
[ATP] = 3.0 mM
What is the typical concentration of ADP in cells?
[ADP] = 0.8 mM
What is the typical concentration of Pi in cells?
[Pi] = 4.0 mM
What is the relationship between delta G values in a series of reactions?
Delta G1 + delta G2 = delta G3
What does it mean if G > 0?
The reaction won’t occur spontaneously
What does it indicate if G2 «_space;0?
Then G < 0, reaction 2 drives reaction 1 forward
Provide an example reaction where glucose is phosphorylated.
Glucose + Pi -> Glucose-6-phosphate + H2O
What is the reversible reaction involving ATP?
ATP + H2O <=> ADP + Pi
What is the reaction between glucose and ATP?
Glucose + ATP <=> Glucose-6-phosphate + ADP
What determines whether a reaction is reversible?
The conditions under which it occurs
When are reactions considered reversible?
When they are in equilibrium
What characterizes enzymes that catalyze reversible reactions?
They are fast, and concentrations of reactants and products are in equilibrium
when do the rules of thermodynamics not apply
when they are on too small a scale
what is an isolated system
no exchange of heat or matter
what is a closed system
able to exchange heat not matter
what is an open system
can exchange heat and matter
what is expansion work
work done by the system on the surroundings when the system changes volume
what is useful work
all other types of work
