Question

Given below are two statements: Statement I: Glucose is found to exist in two different anomeric forms \(\alpha\) and \(\beta\). Statement II: In open chain structure, \(C_2, C_3, C_4\) of glucose and fructose both have same orientation. In light of above statements choose the correct option.

• A. Both statement I and statement II are correct.
• B. Statement I is correct but statement II is incorrect.
• C. Statement I is incorrect but statement II is correct.
• D. Both statement I and statement II are incorrect.

Answer 1

The Correct Option is A

Concept:
Carbohydrates like glucose exist in cyclic forms due to intramolecular hemiacetal formation. This leads to the formation of two stereoisomers called anomers. Additionally, glucose and fructose share identical stereochemistry at certain carbon atoms in their open-chain structures. Step 1: Evaluate Statement I. Glucose forms cyclic hemiacetal structures when the aldehyde group at \(C_1\) reacts with the hydroxyl group at \(C_5\). This produces two stereoisomeric forms: \[ \alpha\text{-D-glucose} \quad \text{and} \quad \beta\text{-D-glucose} \] These differ in the configuration of the anomeric carbon \(C_1\). Thus Statement I is correct. Step 2: Evaluate Statement II. In the open-chain Fischer projections of glucose and fructose: \[ C_2, C_3, C_4 \] have the same stereochemical orientation. This is because fructose and glucose are related keto–aldo sugars and maintain identical configurations at these positions. Thus Statement II is also correct. Step 3: Conclusion. Both statements are correct. \[ \boxed{\text{Option (1)}} \]