Biochemistry Flashcards
What is the first law of thermodynamics?
Energy is neither created nor destroyed
What is the second law of thermodynamics?
When energy is converted from one form to another, some of that energy comes unavailable to do work
What is enthalpy a measure of?
Heat content
What is entropy a measure of?
Disorder or randomness
What is the formula for ∆G?
∆G=∆H - T∆S
∆G=ΔG0’ + RT Ln([C][D]/[A][B])
What is an exergonic reaction?
A reaction in which the value of ∆G is negative, so the reaction is feasible
What is an endergonic reaction?
A reaction in which the value of ∆G is positive so the reaction is not feasible and require an energy input to proceed
What is ΔG0’?
The change in free energy under standard conditions
What are the biochemical standard conditions?
T=298K
Pressure = 1atm
Concentration = 1 mol/dm^3 (except for H+)
pH = 7
What is the value of ∆G at equilibrium?
0
What does a ∆G value near 0 suggest?
The reaction is readily reversible
What is the formula for ΔG0’?
ΔG0’=-RTLnKeq
What is the formula of Keq?
Keq= [C][D] / [A][B]
Are most cellular processes exergonic or endergonic?
Endergonic, so are not feasible
What reaction do most cellular endergonic reactions couple with?
The reaction of ATP and H2O to form ADP, Pi and H+
