Which of the following amino acid ( NH ₂ CH R COOH ) contains polar R group?

Step-by-step solution

The structure of an amino acid is NH ₂CH(R) COOH . The polarity of the R group depends on the presence of functional groups capable of hydrogen bonding or having a dipole moment. Alanine has R = - CH ₃ , which is non-polar. Valine has R = - CH ( CH ₃)₂ , which is non-polar. Glycine has R = - H , which is non-polar. Glutamine has R = - CH ₂ CH ₂ CONH ₂ . The amide group ( - CONH ₂ ) is polar due to the electronegative oxygen and nitrogen atoms, allowing it to participate in hydrogen bonding. Therefore, the R group i