Why is a stacking gel not required in Agarose gel electrophoresis but needed in Polyacrylamide electrophoresis

Answer 1

The quick answer is resolution. Agarose gels are typically used for separating big things, like nucleic acids, based on size and the resolution is generally not as important because the molecules are so big. The acrylamide gel has a lot smaller pore size and typically is used for separating smaller molecules (such as small proteins) because it gives you better separation of molecules that are relatively close in size.

The stacking gel is important because it allows for all of the proteins to hit the resolving gel at the same time so that in your results you can be sure that the bands at the bottom are actually smaller than those above them, not just that they were just lower in the vertical well and started moving first. The stacking gel is lower in pH and in the pores in this portion of the gel are bigger so there is virtually no separation based on size and all proteins across all wells will start running on the resolving gel at the same time.

Answer 2

it depends on the volume of your gel for me my gels are 1.5% gels anything 50ml to 100ml i use 100v for an hour 200ml id used 110V