Collagen's Triple Helix for Structural Strength

Steps:

• Recall collagen's role: provides tensile strength in connective tissues like skin and tendons.
• Examine options: identify which describes collagen's molecular structure enabling rigidity and resistance to stretching.
• Eliminate incorrect features: rule out bonds, folding, and layering that don't match collagen's primary structure.
• Confirm correct feature: triple helix allows parallel alignment for high tensile strength.

Why C is correct:

• Collagen's triple helix structure, formed by three polypeptide chains twisted together, creates a rigid, rope-like molecule that resists pulling forces, as defined in protein biochemistry for extracellular matrix support.

Why the others are wrong:

• A: Layers with different directions describe plywood-like organization in tissues, not collagen's inherent molecular feature.
• B: Ester bonds link carbohydrates or lipids, not adjacent collagen molecules, which use hydrogen and covalent bonds.
• D: Collagen chains form extended helices, not compact folds like globular proteins such as enzymes.

Final answer: C