Chitin has what type of linkage?

• A. Alpha 1-4
• B. Beta 1-6
• C. Alpha 1-6
• D. Beta 1-4

Answer: (D)

Chitin is built from N-acetylglucosamine units joined by beta-1,4 glycosidic bonds. This beta linkage forces the chains to run in straight, extended fashion, which allows many chains to pack tightly and form strong hydrogen bonds between them. The result is a rigid, fibrous structure that provides structural support in insect exoskeletons and fungal cell walls. In contrast, alpha linkages create more curved, helical shapes typical of storage polysaccharides like starch, and beta-1,6 linkages appear in other branched forms, not in the basic chitin backbone.