Question

Which of the following letters represents an amino acid that is uncharged at neutral pH?

1) A
2) B
3) C
4) D

Answer 1

Amino acids can be neutral, polar uncharged, negatively charged, or positively charged at neutral pH. Uncharged amino acids do not gain or lose protons and remain neutral in the pH range 5.0-6.5. Examples include alanine, valine, and leucine.

Step-by-step explanation:

Amino acids are building blocks of proteins and can be categorized based on the nature of their side chains. At a neutral pH, amino acids can have nonpolar, polar but uncharged, negatively charged, or positively charged side chains.

The uncharged amino acids at neutral pH typically have side chains that do not gain or lose protons, and therefore, do not carry any charge. These amino acids will have isoelectric points (pI) ranging between 5.0 and 6.5, indicating that their side chains remain neutral in this pH range. Based on the provided options, amino acids such as alanine (A), valine (V), and leucine (L) are examples of nonpolar, neutral amino acids.