State the difference between the following pairs:
i) α-helix and β-pleated structure
ii) primary and secondary structures of a protein
i) α-helix and β-pleated structure
ii) primary and secondary structures of a protein
Solution
(i) In the \textbf{α-helix} a single chain twists into a right-handed coil held by hydrogen bonds within the same chain; in the \textbf{β-pleated sheet} extended chains lie alongside one another, hydrogen-bonded chain-to-chain, like folded paper.
(ii) The \textbf{primary} structure is the exact sequence of amino acids; the \textbf{secondary} structure is the regular local conformation (helix or sheet) that sequence adopts through N–H···O=C bonding.
(ii) The \textbf{primary} structure is the exact sequence of amino acids; the \textbf{secondary} structure is the regular local conformation (helix or sheet) that sequence adopts through N–H···O=C bonding.
CBSE Class 12 Board · 2002 · Delhi · Subjective