Which of these funtional groups are bases?

Question

Hydroxyl, aldehyde, keto, carboxyl, amino, phosphate, and sulfhydryl? Please provide your sources if possible! Thanks!

Answer 1

As long as the group is capable of accepting a proton, then it is a base.
That narrows it down to -OH, -NH2 and -SH.

I'm not quite sure what you mean by phosphate as an organic group - it sounds more like an anion to me.

And as for "carboxyl", if you mean -COOH, its acidic, but if you mean -COO-, its basic.