What Is a Difference Between Parallel and Antiparallel $\beta$ -Sheet Secondary Structures?
A) Antiparallel

What is a difference between parallel and antiparallel $\beta$ -sheet secondary structures?

A) Antiparallel $\beta$ -sheets have a larger number of stabilizing H bonds between backbone amides than parallel $\beta$ -sheets.
B) Parallel $\beta$ -sheets require a larger loop connecting together the individual peptide strands in the sheet.
C) Parallel $\beta$ -sheets are longer than antiparallel sheets.
D) Parallel $\beta$ -sheets have amino acid side chains alternating up and down, whereas antiparallel side chains alternate down and up.