Question

1. which of the following below is an image of an amino acid (protein)?

Explanation:

Amino acids (the building blocks of proteins) have a central carbon atom bonded to an amino group ($-NH_2$), a carboxyl group ($-COOH$), a hydrogen atom, and a side chain (R - group). The first structure has an amino group ($-NH_2$ - represented as $H_2N -$ here), a carboxyl group ($-COOH$ as $-C(=O)OH$), a hydrogen, and a side chain ($-CH_2SH$). The second structure is a nucleotide (has a phosphate, sugar, and nitrogenous base), and the third is a carbohydrate (a sugar - like ring structure with multiple $-OH$ groups). So the first structure is an amino acid.

Answer:

The first option (the one with the structure containing $H_2N - C - C(=O)OH$ and $-CH_2SH$ side chain) is the image of an amino acid (protein).