Before You Begin
Question #44983
The Question
A biochemical mixture contains each of the following eight compounds in an aqueous solution at : (I) -D-Ribofuranose (II) Adenosine (III) Thymidine 5'-monophosphate (TMP) (IV) 2-Deoxy--D-ribofuranose (V) Maltose (VI) Sucrose (VII) Uridine (VIII) Lactose
What is the total number of compounds in this mixture that possess a free hemiacetal/hemiketal group, undergo mutarotation, and yield a silver mirror when treated with Tollens' reagent ()?
Options
- A.
3
- B.
4
- C.
5
- D.
6
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
Nucleoside vs Nucleotide|Reducing Sugar Criteria|D-Glucose Anomeric Equilibrium
Why This Question Is Tricky
Common Mistakes
The 'Litmus Test' for a reducing sugar is the presence of a free hemiacetal/hemiketal.
Students often fall into the trap of assuming that all nucleotides and nucleosides will reduce Tollens' reagent because they inherently contain a ribose or deoxyribose sugar moiety.
The critical exception tested here is that the formation of the N-glycosidic bond between the C1' anomeric carbon of the sugar and the nitrogenous base effectively locks the anomeric carbon.
This nullifies the ability of the furanose ring to open into the reactive aldehyde form, rendering nucleosides and nucleotides strictly non-reducing.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Biomolecules - Class 12 |
| Concept | Nucleoside vs Nucleotide |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |