Yes, I know, not two, but THREE.

EDIT: Yes, sorry but I did quite a bit of research, searching my notes and textbook for the answer, but all I could find was TWO functional groups as a opposed to the three my guide said there should be. Trust me, I looked quite a bit and there were many conflicting sources with different answers.


closed as off-topic by anongoodnurse, AliceD, jonsca, canadianer, user137 Dec 7 '14 at 7:44

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework questions are off-topic on Biology unless you have shown your attempt at an answer. For more information see our homework policy." – AliceD, jonsca, canadianer, user137
If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ Your original statement of the question is a little bit lazy and lacking in background info. Please reword your question a little bit, and explain more of the background context and your own thinking on the matter, and then I'll update my answer, including the version of it that your professor was probably looking for in the first place. $\endgroup$ – tel Dec 7 '14 at 21:04

Amine, alkyl, and carboxylate.

enter image description here

I'd guess the part that you're having trouble on is that the alpha carbon in the center of the generic AA structure is part of an alkyl functional group


The original answer that I gave might have been too clever for its own good. Depending on how one looks at the question, the third functional group could instead be the functional group of the particular side chain, i.e. for Alanine it would be a methyl group, for Tryptophan it would be an indole group, etc.

  • $\begingroup$ Please read our homework policy before answering questions such as this. We should not be giving out free answers to students who have not even done the most rudimentary thinking about their problem. This doesn't help them learn at all. Instead, I would recommend that you leave a comment asking for which groups they've already come up with, wait for an answer, and then ask them to think about the central carbon, and see if they can come up with the answer themselves. Spoon-feeding direct answers is not terribly helpful. $\endgroup$ – MattDMo Dec 7 '14 at 19:26
  • $\begingroup$ Homework question or no, it seemed interesting enough to merit an answer on this site. Also, having had a couple of hours to think about it the answer I gave is probably wrong, but out of deference to your concerns I won't correct it. $\endgroup$ – tel Dec 7 '14 at 20:41
  • $\begingroup$ as long as the answer is here, you may as well correct it. I also agree that the question is interesting, all I was trying to say is that ideally, you want to get the OP to think about their problem a little bit. Suggest that they edit their question to describe what they've already tried. Some people are genuinly stuck, and it's fine to help them, but it's best to try and get some more info out of them first. $\endgroup$ – MattDMo Dec 7 '14 at 20:46

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