JEE Advanced levelOne or more correct optionsDifficulty 3 of 3bm108
Which statements about secondary structures of proteins are correct?
AIn the alpha-helix the hydrogen bonds are perpendicular to the helix axis.
BBoth structures are held mainly by disulfide bridges.
CIn the beta-pleated sheet, hydrogen bonds join C=O and N-H groups of neighbouring strands.
DIn the alpha-helix, hydrogen bonds join backbone groups of the same chain.
Answer: C, D
Secondary structure arises from backbone hydrogen bonds: within one coil for the alpha-helix (bonds run roughly parallel to the axis) and between side-by-side strands for the sheet. Disulfide bridges belong to tertiary structure.