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this is another brilliant question from TBR's CBT #3 BS. i won't go too far in the specifics since you need to see the passage. the question says:
"The results of gel filtration through agarose beads and carboxymethyl-cellulose beads can BEST be explained by saying that the larger proteins have elution times through agarose beads that are:"
2 of the choices are obviously wrong. you choose between...
1) faster, while carboxymethyl-cellulose beads cause the positively charged proteins to be hindered by attraction to the beads.
or
2) slower, while carboxymethyl-cellulose beads cause the positively charged proteins to be hindered by attraction to the beads.
I chose #2 because larger proteins SHOULD move slower through the beads since they are larger and cannot fit through the pores, right?
they say the correct answer is #1. here is their explanation: "A is the best answer. The carboxymethyl-cellulose beads carry a negative charge, so the column attracts, binds, and consequently retains positively charged proteins. This eliminates choice B and D. Choice A is a better answer than choice C, because the pores in the beads hinder the smaller proteins that pass through them, unlike the larger proteins that bypass the pores in the beads. The best answer is A."
umm, what? how does that make sense? it doesn't. why would larger proteins bypass the pores in the beads over SMALLER ones? that makes absolutely no sense.
before i conclude TBR's tests are garbage (tho still good practice because they usually make me think very hard, excluding a few crappy questions like this), i want to make sure i am correct and not them.
btw, i know it's better not to paste their questions on here, but they offer NO help on their CBTs. it specifically says that on their website. i don't have a tutor or anything, so where else do i get help. thanks guy!
"The results of gel filtration through agarose beads and carboxymethyl-cellulose beads can BEST be explained by saying that the larger proteins have elution times through agarose beads that are:"
2 of the choices are obviously wrong. you choose between...
1) faster, while carboxymethyl-cellulose beads cause the positively charged proteins to be hindered by attraction to the beads.
or
2) slower, while carboxymethyl-cellulose beads cause the positively charged proteins to be hindered by attraction to the beads.
I chose #2 because larger proteins SHOULD move slower through the beads since they are larger and cannot fit through the pores, right?
they say the correct answer is #1. here is their explanation: "A is the best answer. The carboxymethyl-cellulose beads carry a negative charge, so the column attracts, binds, and consequently retains positively charged proteins. This eliminates choice B and D. Choice A is a better answer than choice C, because the pores in the beads hinder the smaller proteins that pass through them, unlike the larger proteins that bypass the pores in the beads. The best answer is A."
umm, what? how does that make sense? it doesn't. why would larger proteins bypass the pores in the beads over SMALLER ones? that makes absolutely no sense.
before i conclude TBR's tests are garbage (tho still good practice because they usually make me think very hard, excluding a few crappy questions like this), i want to make sure i am correct and not them.
btw, i know it's better not to paste their questions on here, but they offer NO help on their CBTs. it specifically says that on their website. i don't have a tutor or anything, so where else do i get help. thanks guy!
