Question

Classify each amino acid by the chemical properties of its side chain (R group) at pH 7·Select the amino acid that fits best in each category. Each amino acid will be used only once. 1. This amino acid has a positively charged R group: Select answer 2. This amino acid has a negatively charged R group! Select answer 3. This amino acid has a neutral polar R group: Sect answer 4 This amino acid has a nonpolar aliphatic R tryptophan aspartate valine arginine Select answer 5. This amino acid has an aromatic R group:

Answer 1

Answer:

. 1. This amino acid has a positively charged R group: ARGININE

2. This amino acid has a negatively charged R group: ASPARTATE

3. This amino acid has a neutral polar R group: NONE

4. This amino acid has a nonpolar aliphatic R: VALINE

5. This amino acid has an aromatic R group: TRYTOPHAN

Explanation:

1) Arginine contains an extra amino group bearing a positive charge, in its chain which imparts basic properties to it

2) Aspartate contains an extra carboxyl group with a dissociable protron. Once the Protron is dissociated, it carries an extra negative charge in its side chain (R)

3) NONE of the amino acids given belong to this group because amino acids with neutral polar R groups contain functional groups that form hydrogen bonds with water. But, this is not the case with tryptophan aspartate valine or arginine

4) Valine has a R group that is hydrocarbon in nature and thus hydrophobic.

5) Trytophan has a benzene ring in its side chain