Question

A polypeptide on complete hydrolysis gives 3 amino acids. How many sequences are possible for that polypeptide?
A. 1
B. 3
C. 6
D. 9

Answer 1

Hint: We know that hydrolysis of a polypeptide yields us an amino acid. Here complete hydrolysis is done. Here the complete amino acid sequence needs to be determined according to the given information.

Complete step by step answer:
We know that amino acids are organic compounds containing amino as well as carboxylic acid groups also. So the general formula of amino acid is ${H_2}N - CH(R) - COOH$ where R refers to different groups for different types of amino acids.
If there is more than one amino group present in it then that is a basic amino acid and if there is more than one carboxylic acid group then that is an acidic amino acid.
Amino acids are the simplest unit of a peptide chain that is linked through peptide bonds which result in the formation of protein.
We know that a polypeptide is a short chain of amino acids linked through a peptide bond. So on hydrolysis, it forms three amino acids. Let say the amino acids formed are glycine, alanine, and phenylalanine. Then the possible combinations of a polypeptide are obtained in the case of glycine, alanine and phenylalanine are as follows
1.Gly-Ala-Phe
2.Gly-Phe-Ala
3.Ala-Gly-Phe
4.Ala-Phe-Gly
5.Phe-Ala-Gly
6.Phe-Gly-Ala
So these are the possible six combinations of the sequence of polypeptides from the hydrolysis of amino acid.

So, the correct answer is Option C.

Note: The possible combination of amino acids in this question is based on the number of amino acids derived from the polypeptide on hydrolysis. So the possible combinations have been provided in the given answer.