Use the results of the two-dimensional electrophoresis gel below to answer the following questions. A) Which protein or proteins have the highest pI value? a. Protein a. b. Proteins d & e. b. Proteins b & c. B) Which protein or proteins have the highest molecular weight? a. Protein a. c. Protein c. b. Protein b. d. Proteins d & e. C) Which protein or proteins have identical molecular weights? a. Proteins a & d. c. Proteins d & e. b. Proteins b & c. d. None. Each has a unique weight.

Alright. So here's a 3 part practice problem broken up into parts a, b, and c. And up above, it says, use the results of the 2 dimensional electrophoresis gel below shown here to answer the following questions. And in part a, it asks, which protein or proteins have the highest p I value or the highest isoelectric point? And we know that isoelectric focusing separates proteins based on their isoelectric point. So for part a, we're only gonna focus on this horizontal axis that goes from left to right. So we're only focused on protein spots as they come from left to right on the gel, and not so much from top to bottom. And so notice that the gradient goes from low gradients on the left to high pH gradients on the right. And so, proteins that have higher isoelectric points stop in the region of the gel that have higher pH's. And so notice that the 2 proteins that have the highest pH's are gonna be the ones that show up furthest to the right, which are protein spots d and e. And so for part a, we can indicate that option c here is the correct answer. Proteins d and e have the highest p I value. And so we can indicate c is correct for part a. Now moving on to part b, it says, which protein or proteins have the highest molecular weight? And because it's referring to molecular weight, we're gonna focus on the SDS PAGE access since SDS PAGE separates proteins based on molecular weight, where larger proteins with higher molecular weights move slower through the gel and so they appear closer to the top, and proteins with smaller molecular weights move faster through the gel and appear closer to the bottom. And so, this protein here is the one that's closest to the top, so it moves the slowest because it has the highest molecular weight. So that's protein spot b. So we can indicate that option b here is the correct answer for part b. Now moving on to our last part here, part c, it asks which protein or, proteins have identical molecular weights? And again, because it's referring to molecular weights, we're looking at the SDS page axis. And notice that there are only 2 proteins that lie on the same portion of the SDS page axis, and none of the other proteins have a partner that has the same molecular weight. So essentially, what that means is that protein spot a and d have the same molecular weight. So that would be answer option a for part c. So we can indicate that a is correct for part c. So that concludes this practice problem, and I'll see you guys in our next video.