Which of the following is $NOT$ an example of a fibrous protein?

$A$ peptide synthesized by the reactions of one molecule each of Glycine,Leucine,Aspartic acid and Histidine will have ..... peptide linkages.

How many of the given compounds will give a positive Biuret test?
Glycine,Glycylalanine,Tripeptide,Biuret.

The Biuret test is not given by:

The structural formula of the amino acid,isoleucine,is:

Identify the acidic amino acid from the following list represented by three-letter symbols.