Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Advanced 2012Paper 1
Exam
JEE Advanced
Year
2012
Paper
Paper 1
Subject
Chemistry
Chapter
Biomolecules

JEE Advanced 2012 · Paper 1 · Chemistry · Biomolecules

The substituents R_ 1 and R_ 2 for nine peptides are listed in the...

The substituents R1R_{1} and R2R_{2} for nine peptides are listed in the table given below. How many of these peptides are positively charged at pH=7.0\mathrm{pH}=7.0 ? PeptideR1R2IHHIIHCH3IIICH2COOHHIVCH2CONH2(CH2)4NH2VCH2CONH2CH2CONH2VI(CH2)4NH2(CH2)4NH2VIICH2COOHCH2CONH2VIIICH2OH(CH2)4NH2IX(CH2)4NH2CH3\begin{array}{|c|c|c|} \hline Peptide & \mathbf{R}_{\mathbf{1}} & \mathbf{R}_{\mathbf{2}} \\ \hline I & \mathrm{H}& \mathrm{H}\\ \hline II & \mathrm{H}& \mathrm{CH}_{3}\\ \hline III & \mathrm{CH}_{2} \mathrm{COOH}& \mathrm{H}\\ \hline IV & \mathrm{CH}_{2} \mathrm{CONH}_{2}& \left(\mathrm{CH}_{2}\right)_{4} \mathrm{NH}_{2}\\ \hline V & \mathrm{CH}_{2} \mathrm{CONH}_{2}& \mathrm{CH}_{2} \mathrm{CONH}_{2}\\ \hline VI & \left(\mathrm{CH}_{2}\right)_{4} \mathrm{NH}_{2}& \left(\mathrm{CH}_{2}\right)_{4} \mathrm{NH}_{2}\\ \hline VII & \mathrm{CH}_{2} \mathrm{COOH}& \mathrm{CH}_{2} \mathrm{CONH}_{2}\\ \hline VIII & \mathrm{CH}_{2} \mathrm{OH}& \left(\mathrm{CH}_{2}\right)_{4} \mathrm{NH}_{2}\\ \hline IX & \left(\mathrm{CH}_{2}\right)_{4} \mathrm{NH}_{2}& \mathrm{CH}_{3}\\ \hline \end{array}

Correct answer

4

Step-by-step solution

Peptides with isoelectric point (pI) more than 7 would exist as cation in neutral solution (pH=7)(\mathrm{pH}=7) which means the given polypeptide is of basic nature, so it must contain two or more amino groups. Hence IV, VI, VIII and IX are correct options.
Practice Biomolecules on Quantrex Academy →

More from Biomolecules

A known artificial sweetener X is composed of 4-chloro-4-deoxy- α -D-galactose and… JEE Advanced 2026The correct statement(s) regarding sugars is(are) Given: Specific rotations of L-(… JEE Advanced 2026In the following reaction sequence, major products X and Y are acyclic monomers. 500 mol… JEE Advanced 2026The incorrect statement from the following with respect to carbohydrates is: JEE Main 2026Which of the following amino acid will give violet coloured complex with neutral ferric… JEE Main 2026Consider the following reactions. Total number of electrons in the π bonds and lone pair… JEE Main 2026Match the LIST-I with LIST-II List-I Deficiency Disease List-II Vitamin A. Scurvy I.… JEE Main 2026Match the LIST-I with LIST-II List-I Amino acid List-II Positive reaction/Test for… JEE Main 2026 Full Biomolecules list All JEE Advanced PYQs