Answer the question on basis of the passage given below:
In zwitter ionic form, amino acids show amphoteric behaviour as they react both with acids and bases.
Except glycine, all other naturally occurring \(\alpha \)- amino acids are optically active, since the \(\alpha \)-carbon atom is asymmetric. These exist both in 'D' and 'L' forms. Most naturally occurring amino acids have L-configuration. L-amino acids are represented by writing the \(NH_2\) group on the left hand side.
The sequence in which amino acids are arranged in protein is called as
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → primary structure
Each polypeptide chain of a protein has its amino acids joined by peptide bonds in a definite sequence. This sequence is the primary structure; changing even one amino acid gives a different protein. The higher levels describe shape, not sequence: secondary (α-helix, β-pleated sheet), tertiary (folding of the whole chain) and quaternary (arrangement of sub-units).
NCERT (2026-27 edition):
Primary Structure of Proteins – “Proteins may have one or more polypeptide chains. Each polypeptide in a protein has amino acids linked with each other in a specific sequence and it is this sequence of amino acids that is said to be the primary structure of that protein. Any change in this primary structure i.e., the sequence of amino acids creates a different protein.”