Practice question
Question
The unique feature of proline that differentiates it from other amino acids is:
Explanation
It has a secondary amino group correctly identifies the characteristic feature or property described in this question. In Amino Acids Basics, specific characteristics define and distinguish biological molecules, organisms, or processes from one another. The feature described by It has a secondary amino group is a defining property that arises from its unique molecular structure, evolutionary history, or physiological role. The other options (It lacks an R group, It has two chiral centers, and It is the most hydrophilic amino acid) describe characteristics of different entities, represent incorrect properties, or apply to the subject under different conditions.