Altius FL 5 C/P Question 23

[IWillMakeIt1]

Hello,

I have no idea why altius consider Leucine has a bulky group as Trp. This is not making any sense to me. If anyone could come up with an explanation please let me know

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[itsalwayssunny96]

I think you mean phenylalanine since F is the 1-letter code for phenylalanine. But anyway, Leucine has a branched R group (iso-butyl) so I am assuming that is why it would be considered a bulky group. I don't think this is a great question, though.

 

[IWillMakeIt1]

I think you mean phenylalanine since F is the 1-letter code for phenylalanine. But anyway, Leucine has a branched R group (iso-butyl) so I am assuming that is why it would be considered a bulky group. I don't think this is a great question, though.

Yeah sorry thats what I meant. anyways, yeah not a great question

 

[aldol16]

They are wrong in assuming that it has the same steric bulk as phenylalanine but this question likely hinges on the fact that they don't say they are equally bulky but rather just that both amino acids are "bulky."

 

[5words]

They are wrong in assuming that it has the same steric bulk as phenylalanine but this question likely hinges on the fact that they don't say they are equally bulky but rather just that both amino acids are "bulky."

So what constitute bulkiness? more than 3 C or is it the branching? I would have chose A as well.

 

[aldol16]

So what constitute bulkiness? more than 3 C or is it the branching? I would have chose A as well.

"Bulkiness," as you correctly imply, is an ambiguous term. I would consider leucine sterically bulky because it's long and branched.