Question 2: The sample is then fractionated by electrophoresis through a _______. As all the proteins now have an _______ to mass ratio, they are separated on the basis of their _____.
INCORRECT. One of the answers is wrong, please try again.
INCORRECT. One of the answers is wrong, please try again.
INCORRECT. One of the answers is wrong, please try again.
CORRECT. The sample is then fractionated by electrophoresis through a polyacrylamide gel. As all the proteins now have an identical charge to mass ratio, they are separated on the basis of their mass.
Question 4: Which the following statements is/are true about the stacking gel?
i. The stacking gel solution contains acrylamide.
ii. It is on the top of the separating gel.
iii. It is used to dilute the protein sample before it enters the main separating gel.
iv. It is into this gel that the wells are formed and the proteins loaded.
INCORRECT. One of them is false.
INCORRECT. One of them is false.
CORRECT. Option i, ii and iv are true, but iii is false because stacking gel is used to concentrate the protein sample into a sharp band before it enters the main separating gel. This is achieved by utilising differences in ionic strength and pH between the electrophoresis buffer and the stacking gel buffer and involves a phenomenon known as isotachophoresis.
Question 5: Each band on the gel represents a different protein (or protein subunit); _____ proteins move through the gel more _____ than_____ proteins and therefore are found nearer the _____ of the gel.
INCORRECT. If the larger proteins move through the gel more rapidly, they should be found near the bottom of the gel.
CORRECT. Smaller proteins move through the gel more rapidly than larger proteins and therefore are found nearer the bottom of the gel.
INCORRECT. If the larger proteins move through the gel more slowly, they should be found near the top of the gel.
INCORRECT. If the smaller proteins move through the gel more slowly, they should be found near the top of the gel.