Peptidoglycan forms sheets that stiffen the cell walls of bacteria. How is the formation of sheets possible?

Answer: Formation of peptide bonds

Explanation:

The structure of peptidoglycan layer found in the cell wall of bacteria consists of linear polymer chains of two alternating amino sugars that are crossed linked by peptide bond ...

The sheet is formed from the cross linkages of the alternating amino-glycan chains by peptide linkages. Hence the word peptidoglycan.

The two amino sugars are N-acetylglucosamine and N-acetylmuramic acid and are linked covalently by β-1,4-glycosidic bond.

Answer is a each strands are joined by peptide bonds.