Final answer:
In beta-pleated sheets, hydrogen bonds form between the carbonyl oxygen atom and the amine hydrogen of different amino acids, with R groups extending out from the sheet, creating a stable structure significant for protein's secondary structure.
Step-by-step explanation:
In beta-pleated sheets, the hydrogen bonds form between the carbonyl oxygen atom from one amino acid and the amine hydrogen of another. The backbone of the polypeptide chain consists of repeating units of amine and carbonyl groups, where the amine group is partially positive and the carbonyl oxygen is partially negative. These hydrogen bonds occur regularly along the polymer chain, creating the characteristic pleated sheet appearance.
The side chains, or R groups, of the amino acids extend above and below the plane of the sheet, allowing the sheet to be relatively flat. The pleated segments of the polypeptide chain may align parallel or antiparallel to each other, resulting in a stable structure that is commonly found in both globular and fibrous proteins, playing a crucial role in their function.
Overall, beta-pleated sheets contribute significantly to the secondary structure of proteins, which is essential for maintaining the protein's overall three-dimensional shape and function.