Answer:
Explanation:
The structural repeating unit of beta sheet is 7 anstrom/2 aminoacids. So,
[tex]\frac{80.5 Angstrom}{3.5} = 23 aminoacids[/tex]
If a segment of a single chain in an antiparallel beta sheet has a length of 80.5 angstrom, then there will be 23 residues in this segment.