Which of the following three polysaccharides primarily serve structural roles in organisms?

• A. Amylopectin, cellulose, and sucrose
• B. Glycogen, chitin, and amylose
• C. Starch, glycogen, and cellulose
• D. Cellulose, chitin, and peptidoglycan

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the role of polysaccharides in organisms. Polysaccharides are long chains of monosaccharides linked by glycosidic bonds. They can serve as energy storage molecules (e.g., starch and glycogen) or structural components (e.g., cellulose and chitin).
2. Step 2: Analyze the structural polysaccharides mentioned in the problem. Structural polysaccharides are those that provide support and protection to cells or organisms. Examples include cellulose (found in plant cell walls), chitin (found in the exoskeletons of arthropods and fungal cell walls), and peptidoglycan (found in bacterial cell walls).
3. Step 3: Eliminate options that primarily serve as energy storage molecules. Amylopectin, glycogen, and starch are storage polysaccharides, not structural ones. Sucrose is a disaccharide and does not serve a structural role.
4. Step 4: Confirm the correct answer by identifying the polysaccharides that are known for their structural roles. Cellulose, chitin, and peptidoglycan are widely recognized as structural polysaccharides in plants, fungi/arthropods, and bacteria, respectively.
5. Step 5: Conclude that the correct answer is 'Cellulose, chitin, and peptidoglycan,' as these polysaccharides are specifically adapted for structural functions in their respective organisms.