Monday, 18 June 2012

Competitive Questions

Self Evaluation


1. Relation between migration rate (R) and molecular weight (W) of DNA molecule during electrophoresis is:

a. R α log1/W.
b. R α W.
c. R α 1/W.
d. R α logW.

2. One has to use a DNA segment in his experiment. He digested a large DNA molecule with restriction endonuclease. If he need a sequence of 10Mb than the best method for him is:

a. Agarose Gel Electrophoresis.
b.  Polyacrylamide gel electrophosis.
c. Contour-clamped homogenous electric-field electrophoresis.
d. 2-D gel electrophoresis.

3. Agarose gel electrophoresis is convenient in separating DNA molecules ranging in size:

a. Less than 100bp.
b. More than 20Kb.
c. 100bp-20kb.
d. Greater than 8Mb.

4. Major Drawback of Pulsed-Field Gel Electrophoresis (PFGE) is:

a. Sample run very fast.
b. Sample don’t run in a straight line resulting in difficulty in analysis
c. Electric field effects the migration rate and give a false interpretation.
d. Large amount of sample is used in this process.

5. For efficient Southern blotting, Gel pretreatment is important. Larger DNA fragments (>10kb) require a longer transfer time than shorter fragments. To allow uniform transfer of a wide range of DNA fragment sizes, the electrophoresed DNA is exposed to a short depurination treatment followed b alkali. Amount of HCl used for depurination is:

a. 0.25 mol/l.
b. 2.5 mol/l.
c. 0.002 mol/l.
d. 0.025 mol/l.

Answers:
1.   a 2. c 3. c 4. b  5. a   

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