CMB1004/L20 Thermodynamics II Flashcards
What is the Boltzmann formula?
S = KB ln(W)
What are microstates?
The number of ways in which energy can be distributed
How many microstates are possible when there is no energy?
1
Why is it impossible to determine the number of microstates in gas?
They are infinite
All possible positions and velocities of gas molecules is too many
What is the 3rd law of thermodynamics?
Entropies of all perfectly crystalline substances are zero at T=0
What is Gibbs free energy equation?
Delta(G) = Delta(H) -TDelta(S)
Free energy change = enthalpy change - temperature x entropy change
When is a reaction favourable?
When free energy change is negative
Delta(G)<0
Describe how water aids protein folding (3).
Water ‘freezes’ around non-polar surfaces
Hiding apolar groups reduces amount of ordered water
Maximises entropy
How do cells carry out unfavourable reactions?
Coupling to favourable reactions
Entropically, how do cells synthesise ATP?
Coupling of ATP synthesis to favourable hydrogen ions transport
Why don’t favourable reactions occur spontaneously?
Activation energy is required
Give 2 mechanisms by which enzymes work.
Hold reactants together
Lower activation energy
