Electrophoresis is a laboratory technique used to separate charged molecules, such as DNA, RNA, and proteins, based on their size and charge. It involves applying an electric field to a gel or solution, causing the molecules to migrate towards the positive or negative electrode. This MCQ on Electrophoresis will help you to study the concept and applications of electrophoresis in biological Research
Biophysics Notes | Biophysics PPT
1). When voltage ‘V’ is applied across a pair of electrode (cathode and anode), a potential gradient ‘E’ is created between the electrodes. We can calculate ‘E’ as:
a. E = V/d
b. E = (1/V) x q
c. E = (Vd)/q
d. E = V + d
2). The velocity (‘v’) of a charged particles in an electric field in a medium can be mathematically expressed as v = Eq/f, where ‘Eq’ and ‘f’ are ________.
a. Eq: Energy; f: Frictional force
b. Eq: Electrical force; f: Gravitational force
c. Eq: Electrical force; f: Frictional co-efficient
d. Eq: Equilibrium constant; f: co-efficient of gravity
3). For the separation of DNA by electrophoresis, which of the following method is commonly used?
a. Agarose – vertical
b. Agarose – horizontal
c. PAGE – vertical
d. PAGE – horizontal
4). Sodium dodecyl sulfate (SDS) used in SDS PAGE is___________.
a. An anionic detergent
b. A cationic detergent
c. A non-ionic detergent
d. An anion exchanger
e. A cation exchanger
5). Function of β-mercaptoethanol in SDS-PAGE is__________.
a. To give negative charges to amino acids in the proteins
b. For the oxidation of disulfide bonds in the proteins
c. For the reduction of disulfide bonds in the proteins
d. For breaking hydrogen bonds in the proteins
6). The ratio of velocity (‘v’) of biomolecule in a medium under constant electric field (‘E’) is called ‘Electrophoretic mobility’ denoted as ‘µ’. ‘µ’ is mathematically expressed as:
a. µ = E/v
b. µ = v/E
c. µ = 1/(Ev)
d. µ = VE
7). In electrophoresis, the electrophoretic mobility (‘µ’) is determines the characteristics of migration of different biomolecules. Which of the following is not having any influence in ‘µ’?
a. Stereochemistry of molecule
b. Size of molecule
c. Shape of molecule
d. Molecular weight
e. Net charge of molecule
8). Electrophoresis is not used for the separation of ________.
a. Nucleic acids
b. Proteins
c. Amino acids
d. Lipids
9). In SDS-PAGE of protein separation, one SDS molecule will binds to __________.
a. Every amino acid
b. Every two amino acids
c. Every three amino acids
d. Every Four amino acids
10). In SDS-PAGE, migration of protein is effected by ____________.
a. Charge of protein
b. Size of protein
c. Net charge of protein
d. All of these
11). In native-PAGE the separation of protein is influenced by ___________.
a. Charge of protein
b. Size of protein
c. pI of protein
d. Both (a) and (b)
e. Both (b) and (c)
12). The main advantage of discontinuous buffer system in SDS and Native PAGE is ________.
a. Conformation of protein is conserved
b. Constantly maintain the charge of proteins
c. Assist in migration of protein
d. Enhance resolution of separation
13). The pH of (i) stacking, (ii) resolving gel and (iii) tank buffer in SDS PAGE is _________ respectively.
a. (i). 8.30 (ii) 8.80 (iii) 6.80
b. (i). 6.80 (ii) 8.80 (iii) 8.30
c. (i). 8.30 (ii) 6.80 (iii) 8.80
d. (i). 6.80 (ii) 8.30 (iii) 8.80
14). The percentage of SDS commonly used in the buffers of SDS PAGE is __________.
a. 0.1 %
b. 1.0 %
c. 10 %
d. 1 – 10 %
15). The role of urea in PAGE separation of DNA is to _______.
a. Act as anion
b. Act as cation
c. Helps to denature the DNA
d. Provide buffer stability of the gel
16). The role of APS in SDS PAGE is to________.
a. Act as a catalyst in the polymerization of acrylamide
b. Act as a source of free radicals
c. Act as a bridge between acrylamide and bis-acrylamide
d. Act as a pore builder in the polymerized gel
17). The ‘tracking dye’ used in SDS PAGE will be ______.
a. Anionic
b. Cationic
c. Non-ionic
d. Amphipathic
18). Which of the following is used as a ‘tracking dye’ in SDS-PAGE of protein?
a. Bromophenol blue
b. Xylene cyanol
c. Orange G
d. Both (a) and (b)
e. All of these
19). Glycerol is added to protein samples before they are loaded to the ‘wells’ of PAGE. The function of glycerol is to _______.
a. Stabilize protein structure
b. Provide density to the sample
c. Helps to bind SDS to the protein
d. Helps to reduce disulfide bonds by β-mercaptoethanol
20). For the better resolution of minute protein bands in SDS-PAGE, which of the following staining method is advised?
a. CBB Staining
b. Silver staining
c. Avidin staining
d. All of these
Answers with explanations:
1. Ans. (a). E = V/d
2. Ans. (c). Eq: Electrical force; f: Frictional co-efficient
3. Ans. (b). Agarose – horizontal
4. Ans. (a). An anionic detergent
5. Ans. (c). For the reduction of disulfide bonds in the proteins
6. Ans. (b). µ = v/E
7. Ans. (a). Stereochemistry of molecule
8. Ans. (d). Lipids
9. Ans. (b). Every two amino acids
10. Ans. (b). Size of protein
11. Ans. (d). Both (a) and (b).
12. Ans. (d). Enhance resolution of separation
13. Ans. (b). (i). 6.80 (ii) 8.80 (iii) 8.30
14. Ans. (a). 0.1%
15. Ans. (c). Helps to denature the DNA
16. Ans. (b). Act as a source of free radicals
17. Ans. (a). Anionic
18. Ans. (e). All of these
19. Ans. (b). Provide density to the sample
20. Ans. (b). Silver staining