Question

The building blocks of proteins are ______ naturally occurring amino acids, small molecules that contain a free amino group (NH2) and a free carboxyl group (COOH).

(a) ten

(b) twenty

(c) nine

(d) nineteen

I had been asked this question in class test.

My enquiry is from Protein Structure Basics topic in portion Structural Bioinformatics of Bioinformatics

Answer 1

Right option is (b) twenty

The best explanation: Both of these groups are linked to a central carbon (Cα), which is attached to hydrogen and a side chain group (R). Amino acids differ only by the side chain R group. The chemical reactivities of the R groups determine the specific properties of the amino acids. Amino acids can be grouped into several categories based on the chemical and physical properties of the side chains, such as size and affinity for water.