Which polymer is a structural polysaccharide in plant cell walls, wood, and paper?

Which polymer is a structural polysaccharide in plant cell walls, wood, and paper?

• A. Glycogen
• B. Starch
• C. Cellulose
• D. Chitin

Answer: (C)

Cellulose is the structural polysaccharide that strengthens plant cell walls, wood, and paper. It is built from glucose units linked by beta-1,4-glycosidic bonds, forming long, straight chains that readily align and hydrogen-bond to create strong microfibrils. This rigid, fibrous network provides the tensile strength and rigidity essential for plant structure, which is why it is the main component of wood and the fibrous material in paper. Glycogen and starch are storage polysaccharides with alpha linkages, leading to branched or helical structures rather than strong fibers, so they don’t serve a structural role in plant walls. Chitin is also structural but is composed of N-acetylglucosamine and is found in fungal cell walls and arthropod exoskeletons, not in plants.

Cellulose is the structural polysaccharide that strengthens plant cell walls, wood, and paper. It is built from glucose units linked by beta-1,4-glycosidic bonds, forming long, straight chains that readily align and hydrogen-bond to create strong microfibrils. This rigid, fibrous network provides the tensile strength and rigidity essential for plant structure, which is why it is the main component of wood and the fibrous material in paper. Glycogen and starch are storage polysaccharides with alpha linkages, leading to branched or helical structures rather than strong fibers, so they don’t serve a structural role in plant walls. Chitin is also structural but is composed of N-acetylglucosamine and is found in fungal cell walls and arthropod exoskeletons, not in plants.