Question

Identify neutral amino acid from following list represented by three letter symbols.

• A. Arg
• B. Asp
• C. Leu
• D. His

Hint:

Memorize the extremes to save time!
Only 2 are Acidic: Aspartic acid (Asp) & Glutamic acid (Glu).
Only 3 are Basic: Histidine (His), Arginine (Arg), & Lysine (Lys).
Almost everything else on a standard list is Neutral!

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Amino acids are classified as acidic, basic, or neutral based on the number of amino groups ($-NH_2$) and carboxyl groups ($-COOH$) in their side chains.

Step 2: Formula Application:
1. Acidic: More $-COOH$ than $-NH_2$. 2. Basic: More $-NH_2$ than $-COOH$. 3. Neutral: Equal number of $-NH_2$ and $-COOH$.

Step 3: Explanation:
- Arg (Arginine): Basic (contains guanidino group). - Asp (Aspartic acid): Acidic (contains extra carboxyl group). - His (Histidine): Basic (contains imidazole ring). - Leu (Leucine): Neutral (contains a simple hydrocarbon alkyl side chain).

Step 4: Final Answer:
Leucine (Leu) is a neutral amino acid.