Thermodynamics and HP effect Flashcards
tendency of non-polar substances
aggregate in aqueous solution and exclude water molecules
biological systems
stabilising phospholipid membrane therefore formation of cells and cellular compartment
protein folding into 3D structure to be able to function
self assembly of lipids
bilayer sheets , micelles etc
free energy representation in unfolded state of protein
many formation causing large conformational entropy
free energy representation in folded native state
approximated by 1 formation causing a low conformational entropy
more folding
decreases free energy of folding
mixing substances equation
DG{mixing} = DH{mixing} - TDH{mixing}
finding DH{mixing}
2DH{a-b} - DH{a-a} - DH{b-b}
DH{a-b}
interaction energy A and B
if DG*>0
equilibrium is towards demixed state
DH* being close to 0
no strong contribution of interactions between molecules and water molecules - favour mixing
some slightly -ve that favour mixing
why TDS* is large and negative
entropy drives reaction towards demixing
it’s counterintuitive as mixing of 2 molecules in solution
therefore entropically favourable
if corner is replaced by HC atom
calculating no. microstates of water
halves as they cannot form H-bonds
therefore W=3
calculating change in entropy in presence of HC atom equation
DS* = S{in water} - S{onhydrophobic - surface}
model of water molecule
has 4 neighbours
forming 2 H-bonds
loss of entropy of water
caused by introduction to single HC atom perturbing orientation freedom of water (1.7KJmol-1/0.41Kcalmol-1)
joules to calories
1j = 0.24cal
2 major organising factors in living system
membrane assembly
protein folding
membrane assembly in living system
minimises exposure of HC chains to water maximising entropy of water in presence of phospholipid
protein folding in living system
minimising exposure of HC chain containing side chains to water - maximising entropy of water
core of scientific endeavor
data gathering
analysis
model making
interpretation
