See image — Biomolecules Chemistry Question

💡 Solution & Explanation

Concept: D-Glucose can exist in multiple stereoisomeric forms due to its open-chain and cyclic (pyranose) structures. Step 1: Identify the forms of D-Glucose. D-Glucose exists in the following stereoisomeric forms: 1. α-D-Glucopyranose (cyclic, alpha anomer) 2. β-D-Glucopyranose (cyclic, beta anomer) 3. Open-chain (aldehyde) form Step 2: Consider mutarotation and equilibrium forms. In aqueous solution, D-glucose establishes an equilibrium between: - α-D-Glucopyranose - β-D-Glucopyranose - Open-chain aldehyde form These are the three well-known interconvertible forms of D-glucose in solution (mutarotation involves these three forms predominantly). Step 3: Why not 2? Two forms would only account for the two anomers (α and β), ignoring the open-chain form. Step 4: Why not 4 or 5? While furanose forms exist in trace amounts, the question asks about the commonly recognized/distinct stereoisomeric forms of D-glucose, which are the three primary forms: α-pyranose, β-pyranose, and open-chain. The standard answer recognized in this context is 3. Therefore, the correct answer is B.