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Question #45242
The Question
In an experiment, a skeletal muscle neuromuscular junction (NMJ) is exposed to a chemical agent that disrupts the disulfide and hydrogen bonds of the postsynaptic membrane proteins. Another NMJ is treated with the neurotoxin curare. Both treatments result in flaccid paralysis. Which of the following statements correctly distinguishes the molecular basis of paralysis in these two scenarios?
Options
- A.
The chemical agent causes irreversible loss of the quaternary structure of ACh receptors, while curare reversibly competes with ACh for the receptor's binding site.
- B.
The chemical agent prevents the exocytosis of ACh from presynaptic vesicles, while curare irreversibly binds to the motor end plate.
- C.
Both agents cause irreversible flaccid paralysis by preventing the generation of an end-plate potential, but through different allosteric sites.
- D.
The chemical agent competitively inhibits the enzyme acetylcholinesterase, while curare denatures the ligand-gated sodium channels.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Neuromuscular_Junction_Signal|Protein_Denaturation_Specificity|ACh_Receptor
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating 'Biomolecules' (protein denaturation) with 'Neural Control' (synaptic transmission).
Students often memorize that toxins block the NMJ but fail to distinguish between reversible competitive inhibition (pharmacological antagonism) and irreversible structural destruction (denaturation).
The trap lies in assuming both agents cause irreversible damage or confusing pre- and post-synaptic mechanisms.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biomolecules - Class 11 |
| Concept | Protein Denaturation Specificity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |