Question

How many tripeptides are possible when following three amino acids make tripeptide? (No amino acid should repeat twice) 
(A) Glycine 
(B) Alanine 
(C) Valine 
 

• A. 4
• B. 6
• C. 8
• D. 9

Hint:

Peptide sequences are counted using permutations, not combinations.

Answer 1

The Correct Option is B

Step 1: Understand tripeptide formation.
A tripeptide consists of three amino acids linked in a specific order.
Order of amino acids matters.
Step 2: Identify the amino acids.
Available amino acids are Glycine (G), Alanine (A) and Valine (V).
No repetition is allowed.
Step 3: Calculate number of possible arrangements.
Number of tripeptides = number of permutations of 3 different amino acids.
\[ = 3! = 6 \]
Step 4: List the possible tripeptides.
GAV, GVA, AGV, AVG, VAG, VGA