Chapter 9
1. At isoelectric pH, protein is
(a) Positively charged (b) Negatively charged (c) Neutral
Ans: (c)
2. What major problems in electrophoresis arises due to joule heating effects?
Ans: (a) Density difference occurs leading to free convection.
(b) Temperature increase degrades protein.
3. How joule heating is prevented?
Ans: (a) Efficient cooling.
(b) Electrophoresis is used in a gel/membrane to prevent cooling.
4. How electroosmosis is prevented in electrophoresis?
Ans: Use of material for gel having low residual charge like ployacrylamide.
5. In a batch page electrophoresis, µosm=0. Mobilities of two proteins are µA =5X10-5
cm2/V.s and µB= 3X10-5cm2/V.s. DA=1.5X10-7 cm2/s and DB=1.2X10-7 cm2/s.
E=200 V/cm; t=4 hours. Find resolution (R).
Ans
2
5
510 .2
5
310 .
cm
Avs
cm
Bvs
exp
Z
Et
AA
2
5
5 10 200 (4 3600)
.
cm v s
vs cm
144cm
exp
Z
Et
BB
