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Question #44996
The Question
An aqueous solution contains an equimolar mixture (1 mole each) of four disaccharides: Sucrose, Lactose, Maltose, and Cellobiose. Four identical aliquots of this solution (each containing 1 mole of all four disaccharides) are subjected to different hydrolytic conditions at and optimal pH:
Aliquot I: Treated with Invertase (strictly specific to sucrose). Aliquot II: Treated with -galactosidase (strictly specific to -D-galactoside linkages). Aliquot III: Treated with Maltase (strictly specific to -(14)-D-glucosidic linkages). Aliquot IV: Heated with dilute aqueous \ce{H2SO4} until complete chemical hydrolysis occurs.
Assume all enzymatic and chemical hydrolyses proceed to 100% completion. Let be the total moles of free D-glucose molecules present in the final mixture of Aliquot . Let be the total moles of reducing sugar molecules present in the final mixture of Aliquot .
Calculate the value of .
Options
- A.
31
- B.
34
- C.
33
- D.
29
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Exception_Exposure
Learn to identify edge cases and boundary exceptions that JEE examiners hide in math problems.
Concepts Behind This Question
Disaccharide Hydrolysis Products|Enzyme Specificity 'Lock and Key'|Glycosidic Linkage Geometry
Why This Question Is Tricky
Common Mistakes
This problem tests the 'Lock and Key' specificity of enzymes based on stereochemistry ( vs glycosidic linkages) and the strict definition of reducing sugars.
The primary trap is assuming Maltase will hydrolyze Cellobiose because both Maltose and Cellobiose are D-glucose dimers with 1,4-linkages.
However, Maltase is strictly specific to -(14) linkages, while Cellobiose has a -(14) linkage, rendering it immune to Maltase.
Additionally, it tests the knowledge that Fructose (a ketose) is a reducing sugar due to its ability to isomerize via the Lobry de Bruyn-van Ekenstein transformation, and that Sucrose is a non-reducing sugar.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Biomolecules - Class 12 |
| Concept | Disaccharide Hydrolysis Products |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |