CMB1004/L24 Biophysics Revision

Question 1

What is the equation for rate of decrease of reactants?

Answer 1

Rate = k[A]^x[B]^y
Where x and y are orders of reaction w.r.t. A and B

Question 2

What is the equation for the equilibrium constant?

Answer 2

Kc = [C]^c[D]^d/[A]^a[B]^b

Question 3

What is the equation for the acid dissociation constant?

Answer 3

Ka = [H+][A-]/[HA]

Question 4

What is the Henderson-Hasselbach equation?

Answer 4

pH = pKa + log([A-]/[HA])

Question 5

How do macromolecules contribute to cellular osmolarity?

Answer 5

Little, as they have relatively low copy numbers
Due to charge, they attract counterions which do contribute to osmolarity

Question 6

Describe the Donnan problem. (2)

Answer 6

Small inorganic ions leak inside the cell due to attraction between them and impermeable macromolecules
Equilibrium would be reached with higher osmolarity outside the cell

Question 7

What does the Nernst equation tell us?

Answer 7

The electrical potential when ions have stopped flowing across a membrane

Question 8

Give an equation linking voltage, energy and charge.

Answer 8

V = E/q
E = qV

Question 9

Where does the Nernst equation come from? (2)

Answer 9

Electrical potential due to moving a charge in an electric field
Entropy change due to mixing

Question 10

What does weight by volume (w/v%) correspond to?

Answer 10

The grams of a solute per 100ml of water

Question 11

If 20g or glucose is added to 1L of water, what is the w/v%?

Answer 11

2%

Question 12

What is the Boltzmann formula?

Answer 12

S = KB*ln(W)

Question 13

Define a microstate.

Answer 13

A microscopic arrangement of all the positions and energies of gas particles