Indicate whether each of the following molecules is an α-amino acid or not, and explain why.
a.

Question

Indicate whether each of the following molecules is an α-amino acid or not, and explain why.

a. Structural formula of an amino acid showing its α-amino group, carboxyl group, and side chain.

Accepted Answer

All right. Hi, everyone. So this question is asking us are the following molecules alpha amino acids and why here we have three compounds to examine. So first, it's worth mentioning what amino acids actually look like and what an alpha amino acid, in particular, its amino acids are organic compounds composed of a carboxylic acid, an amine and a side chain. But what's unique about the alpha amino acid is the positioning of all of these groups together starting off with the carboxylic acid recall that the carboxylic acid contained a car bole or a carbon double bonded to an oxygen. Now, Greek letters can be used to describe the positions of carbon atoms in the parent chain relative to the car bono itself. Now, the alpha carbon or the alpha position is the carbon atom directly adjacent to the carbon. So an alpha amino acid is defined as an amino acid where the amino group is attached to the alpha position relative to the carbo of the carboxylic acid. The side chain for that matter abbreviated here as an R group is also attached to the alpha carp. So for all three structures, the first thing I'm going to do here is identify where the alpha position happens to be. So the first thing ill do is locate the car bono in each compound and then label the carbon atom right next to it. So let's go ahead and examine the first molecule. In the first molecule, we have a carboxylic acid group. We have the car bal as well as a hydroxy group or an O group attached to the carbon carbon. And we also have an amino group or an NH two. So in addition to this, we also have an ocular side chain branching off of the alpha carbon as well. But because the amino group is attached to the alpha position relative to the car bono, this is in fact a compound one is in fact an alpha amino acid because the amino group is on the alpha carbon. But let's go ahead and examine compound two. Now, compound two, once again, has a carboxylic acid towards the right of the structure. And we also have an amino group. But what's interesting here is that the amino group is actually not on the alpha carbon. The amino group is not connecting to the alpha carbon, rather the amino group is connecting to a carbon atom that is two spaces away from the car bono itself. So this means it's actually on the beta carbon. So because compound two has its amino group on the beta position, it is not going to be an alpha amino acid. So now let's talk about compound three. Earlier, we did identify the car bottle or compound three. But what I want to point out here is the fact that attached to the car bal is an amino group, not a hydroxy group to make it a carboxylic acid. So because of this, the functional group present is actually an amide. It is not a carboxylic acid. And because there's no carboxylic acid compound three is not an alpha amino acid either because there is no carboxylic acid present and there you have it. So of the three compounds provided only number one is an alpha amino acid. But because we have to describe why in our final answer, I actually went ahead and pre wrote the final answers just to save time because you don't have to watch me write the whole thing. So I'll scroll down here and show you for part one, the molecule is an alpha amino acid because it has an amino group connected to the alpha position relative to the car bono carbon. For part two, the molecule is not an alpha amino acid because it does not have an amino group connected to the alpha position relative to the carbon carbon. And for part three, the molecule is not an alpha amino acid because it does not have a carboxylic group referring to the carboxylic acid and there you have it. So with that being said, thank you so very much for watching and I hope you found this helpful.

Indicate whether each of the following molecules is an α-amino acid or not, and explain why.
a.

Verified video answer for a similar problem:

Key Concepts

α-Amino Acid Structure

Classification of Amino Acids

Role in Protein Synthesis