Final answer:
Every helical turn in an alpha helix has 3.6 amino acid residues. The R groups of the polypeptide protrude out from the helix chain. In the ß-pleated sheet, pleats are formed by hydrogen bonding between atoms on the backbone of the polypeptide chain.
Step-by-step explanation:
Every helical turn in an alpha helix has 3.6 amino acid residues. The R groups (the variant groups) of the polypeptide protrude out from the a-helix chain. In the ß-pleated sheet, the "pleats" are formed by hydrogen bonding between atoms on the backbone of the polypeptide chain. The R groups are attached to the carbons and extend above and below the folds of the pleat.
The pleated segments align parallel or antiparallel to each other, and hydrogen bonds form between the partially positive nitrogen atom in the amino group and the partially negative oxygen atom in the carbonyl group of the peptide backbone. The a-helix and ß-pleated sheet structures are found in most globular and fibrous proteins and they play an important structural role.