lab 8: protein separation using SDS-PAGE

1. SDS-PAGE is primarily used to determine:

C. Number, abundance, and molecular weight of proteins

2. Electrophoresis separates molecules based on movement in:

C. Electric field

3. Polyacrylamide gels are preferred because they have:

B. High resolving power and physical stability

4. Polymerization of gel involves acrylamide and:

C. N,N’-methylene-bis-acrylamide

5. Catalyst system for gel formation includes:

C. Ammonium persulfate + TEMED

6. Standard gel percentage used for protein separation:

B. 7.5%

7. SDS denatures proteins and gives them:

B. Uniform negative charge

8. Mercaptoethanol assists denaturation by:

B. Reducing disulfide bonds

9. Electrophoretic velocity equation shows mobility depends on:

B. Size, charge, and friction coefficient

10. Protein sample treatment buffer includes:

B. SDS + mercaptoethanol + glycerol + tracking dye

11. Samples are boiled for:

B. 5 minutes

12. Purpose of stacking gel:

B. Concentrate samples into sharp bands

13. Running buffer contains:

A. Tris + glycine + SDS

14. Basic pH of running buffer is:

8.8

15. Gels are run at:

C. 30 amps per gel

16. Progress of electrophoresis is monitored using:

B. BPB dye front

17. Protein visualization based on:

B. Coomassie blue binding

18. Destaining allows:

B. Removal of excess dye to reveal protein bands

19. Gel storage short-term uses:

B. 5% acetic acid

20. Long-term storage achieved by:

B. Drying between cellophane sheets

21. Acrylamide concentration of resolving gel:

B. 7.5%

22. Role of glycine in running buffer relates to:

A. Charge shifting between stacking vs resolving gel

23. Running buffer and gel pH ensures:

B. Proper separation conditions

24. Would separation occur at pH 3.5?

B. No, separation fails

25. Function of stacking gel is to create:

B. Thin concentrated protein zones

26. Without stacking gel, proteins would:

B. Enter resolving gel dispersed → poor resolution

27. Electrophoresis can estimate MW from band:

B. Band migration relative to standards

28. Protein denaturation prior to loading ensures:

B. Uniform charge/shape for size-based separation

29. Resolving gel buffer pH:

B. 8.8

30. Stacking gel buffer pH:

B. 6.8