Question

Which of the following sets consists only of essential amino acids?

• A. Alanine, tyrosine, cystine
• B. Leucine, lysine, tryptophan
• C. Alanine, glutamine, lysine
• D. Leucine, proline, glycine

Hint:

Essential amino acids must come from diet; examples: leucine, lysine, tryptophan, valine, methionine.

Answer 1

The Correct Option is B

Step 1: Meaning of essential amino acids.
Essential amino acids are those which cannot be synthesized by the human body and must be obtained from diet.
Step 2: Check the given amino acids.
Essential amino acids include:
Leucine, Lysine, Tryptophan, Valine, Isoleucine, Methionine, Threonine, Phenylalanine, Histidine.
Step 3: Analyze options.
(A) Alanine and tyrosine are non-essential \(\Rightarrow\) incorrect.
(C) Alanine and glutamine are non-essential \(\Rightarrow\) incorrect.
(D) Proline and glycine are non-essential \(\Rightarrow\) incorrect.
(B) Leucine, lysine, tryptophan are all essential \(\Rightarrow\) correct.
Final Answer:
\[ \boxed{\text{(B) Leucine, lysine, tryptophan}} \]