Question

The list given below contains essential amino acids that are basic (\(X\)) and also non essential amino acids that are neutral \(Y\). \(X\) and \(Y\) respectively are:
• [a)] Lysine
• [b)] Alanine
• [c)] Serine
• [d)] Arginine
• [e)] Tyrosine

• A. \( X = b, c, e \quad Y = a, d \)
• B. \( X = a, d \quad Y = b, c, e \)
• C. \( X = a \quad Y = b, d, e \)
• D. \( X = a, b, c \quad Y = d, e \)

Hint:

To remember the basic amino acids instantly, use the mnemonic "HAL" (Histidine, Arginine, Lysine). Since Lysine (\(a\)) and Arginine (\(d\)) are the main basic amino acids from this list, grouping them together under category \(X\) lets you lock down the correct answer choice immediately!

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Amino acids are classified by two main criteria:
1. Nutritional Requirement: "Essential" amino acids cannot be made by the body and must come from food. "Non-essential" ones can be synthesized internally.
2. Side-chain Chemistry: "Basic" amino acids have extra amine ($-NH_2$) groups in their side chains. "Neutral" amino acids have an equal number of amine and carboxyl groups.
Step 2: Detailed Explanation:
Let's analyze the given list:
- Lysine (a): Essential and Basic (contains an extra $-NH_2$ group). Fits Category X.
- Arginine (d): Semi-essential (usually classed as essential for exams) and Basic (contains a guanidino group). Fits Category X.
- Alanine (b): Non-essential and Neutral (alkyl side chain). Fits Category Y.
- Serine (c): Non-essential and Neutral (polar side chain). Fits Category Y.
- Tyrosine (e): Non-essential and Neutral (aromatic side chain). Fits Category Y.
Thus, $X = \{a, d\}$ and $Y = \{b, c, e\}$.
Step 3: Final Answer:
This maps to option (B).