Which statement correctly matches a structural polysaccharide with its typical biological role?

Which statement correctly matches a structural polysaccharide with its typical biological role?

• A. Glycogen as energy storage
• B. Cellulose as structural in plants
• C. Chitin as lipid
• D. Starch as structural

Answer: (B)

Understanding this question comes down to how structural polysaccharides differ from storage polysaccharides. cellulose is the classic structural polymer in plants because its glucose units are linked by β-1,4 bonds, which produce straight chains that can align parallel and form extensive hydrogen-bonded microfibrils. These fibers give plant cell walls their rigidity and tensile strength, supporting the plant body. Glycogen and starch are built with α-linked glucose in branched forms, making them compact and easy to enzymatically break down for quick energy release, which is why they serve as energy storage rather than structural components. Chitin is structurally important in fungi and the exoskeletons of arthropods, but it is not a lipid—it's a polysaccharide similar in role to cellulose in lending support and protection.

Understanding this question comes down to how structural polysaccharides differ from storage polysaccharides. cellulose is the classic structural polymer in plants because its glucose units are linked by β-1,4 bonds, which produce straight chains that can align parallel and form extensive hydrogen-bonded microfibrils. These fibers give plant cell walls their rigidity and tensile strength, supporting the plant body.

Glycogen and starch are built with α-linked glucose in branched forms, making them compact and easy to enzymatically break down for quick energy release, which is why they serve as energy storage rather than structural components. Chitin is structurally important in fungi and the exoskeletons of arthropods, but it is not a lipid—it's a polysaccharide similar in role to cellulose in lending support and protection.