Beta (?) sheets are a type of secondary structure in proteins. A segment of a single chain in an antiparallel? sheet has a length of 94.5 Å. How many residues are in this segment?

The correct answer is 27 residues.

Explanation:

In an antiparallel beta sheet, there is a repeat for every 7 Angstrom units and the number of residues is two for every repeat. In an antiparallel sheet that exhibits a length of 94.5 Angstrom, the number of residues can be determined by using the following formula:

2 residues per every 7 Angstrom,

Length of the given segment is 94.5 Angstrom

Number of residues in this segment are:

= (number of segments) * (residues per segment)

= (94.5/7) * 2

= 13.5 * 2

= 27 residues.

Thus, the number of residues in this segment is 27.