Variant 4c- electrokinetic potential of cells

Question 1

Aim of study

Answer 1

To estimate electokinetic potential and electrophoretic mobility of erythrocytes in medium of different ionic strength

Question 2

Stern model

Question 3

Describe shortly the experimental work and measurements for determination of the
electrophoretic mobility. Write the equation for its calculation and explain the factors
involved (9)

Answer 3

• 3 diff RBC suspensions, including one with Nacl
• 2 electrodes with semipermeable membrane connected to ammeter. Chamber covered in thermostate and look through microscope
• determine velocity

V=l/t

U=V/E

Question 4

Which biological processes are influenced by the outer surface electrical charge of the RBC?

Answer 4

electrostatic repulsion- dterine reversible aggregation/agluttination

aging- enzymatic cleavafe of charge on old cells may affect interactions, comporomise blood flow

Electrophorectic mobility estimation- since other molecules can adsorb onto cell surface

Question 5

Write the definition equation for the coefficient of permeability for a hydrophobic substance,
explain the parameters involved. (8)

Answer 5

P=KxD/L

k= partition coefficient

D= diffusion coefficent

L=thickeness

k= cmi/ci = cmout/cout

Question 6

Write down the equation for Goldmann-Hodgkin-Katz, explain the parameters involved in it
(9)

Answer 6

Potential= -RT/z ln P…………..(k) (Na)(Cl)