Question

Which of the following is the example of acidic amino acid?

• A. Lysine
• B. Glutamic acid
• C. Aspartic acid
• D. Both B and C

Answer 1

The correct option is D Both B and C

An amino acid contains an amino group, a carboxylic group both attached to the same carbon. The various amino acids differ with respect to the side chain (R group) attached to their alpha-carbon. Amino acids can be classified on the properties of their side chain, in particular their polarity or tendency to interact with water at physiological pH. The polarity of the side chain varies widely from non polar and hydrophobic to highly polar and hydrophilic.Amino acids can be classified in the following four groups
1. Amino acids with polar side chain - glycine, alanine, valine, leucine, isoleucine, proline, methionine, tryptophan
2. Amino acids with uncharged polar side chain-six in number. Serine, threonine, cysteine, aspargine, glutamine and tyrosine
3. Amino acids with charged polar side chain
Positively charged R group : Lysine, arginiine, histidine.
Negatively charged R group : Aspartic acid and glutamic acid. So both glutamic acid and aspartic acid are acidic amino acids.