Question

which functional groups are present in proteins? see figures below. if you are having trouble seeing the figure then click this link to see the figure in a new window: protein functional groups need a hint? check out this version of the figure that has all of the functional groups circled: protein functional groups circled ☐ sulfhydryl ☐ hydroxyl ☐ amino

Explanation:

1. Sulfhydryl: The group \(-SH\) (seen in one of the structures as \(CH_2 - SH\)) is the sulfhydryl functional group.
2. Hydroxyl: The group \(-OH\) (seen as \(CH_2 - OH\) in one structure and also the \(-OH\) in the carboxyl group \(-COOH\)) is the hydroxyl functional group.
3. Amino: The group \(-NH_2\) (or \(-NH_3^+\) in protonated form, seen as \(-N - H_2\) or \(-N - H_3\) in the structures) is the amino functional group. Also, the carboxyl group \(-COOH\) (with \(-C(=O)-OH\)) is present, but among the given options, amino, hydroxyl, and sulfhydryl are identifiable from the structures.

Answer:

Sulfhydryl, Hydroxyl, Amino (all three options should be selected as they are present: Sulfhydryl (\(-SH\)), Hydroxyl (\(-OH\)), Amino (\(-NH_2\) or related amino - containing groups in the protein - building amino acid structures shown).