2. Bio-energetics and molecular machines Flashcards
Free energy is…
G = U -TS
Probability of being in a state with free energy G is proportional to..
number of microstates * exp(-G/kT)
For a spontatneous process, the change in free energy is…
positive
Derive the diffusion equation
Derive Einstein’s relation by considering a random walk under a force F
Derive Einstein’s relation by considering drift velocity at low Re
Law of mass action =
the number of particles that transition between two states is propotional to teh number of available particles
J_12 = k_12 [A_1]
Principle of detailed balance =
If a system is in equilibrium then each of its degress of freedom is also in equilibrium
Dissociation constant at equilibrium is
[A][B]/[AB] = k_off/k_on = K_D
What are biological membranes made of?
Phospholipid bilayers
Describe the structure of an amphiphile
Contains a head (hydrophilic) and hydrocarbon tails (hydrophobic).
The head is either neutral or negative.
The size of the head determines how the amphiphiles self organise.
A negative head has a larger effective size.
Name the three common amphiphile phases in water and state when they are likley to form
Derive the conditions for formation of a sphere, cylinder and bilaryer
Derive the energy of a bilayer sphere
Energy to move an ion from water to hydrocarbon
e^2/(8πE_0 R) (1/E_membrane - 1/E_water
where E is epsilon
Capicitance is given by
A E_0 E_r / t
Nernst equation
C2/C1 = k12/k21 = exp(-q(V2-V1)/kT)
Derive the Poisson-Boltzmann equation
PMF is driven by
electrical potenital plus a concentraion gradient
How is pmf generated?
active transport of proteins across a membrane