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Question #46880
The Question
In Periplaneta americana, the midgut (mesenteron) maintains a highly alkaline pH. If an ingested chemical agent drastically lowers the midgut pH to an acidic range, which of the following best explains the primary mechanism for the resulting failure in amino acid absorption and its secondary physiological consequence?
Options
- A.
The acidic shift alters the zwitterionic state of amino acids, disrupting their recognition by epithelial transporters, which subsequently alters the nitrogenous waste load on Malpighian tubules.
- B.
The acidic environment dissolves the chitinous cuticular lining of the midgut, preventing the diffusion of amino acids and causing immediate autolysis of the hepatic caeca.
- C.
The influx of H+ ions reverses the active transport gradient, causing amino acids to be converted into ammonia and excreted directly through the spiracles.
- D.
The acidic pH prematurely activates alkaline proteases, which rapidly degrade amino acids into uric acid within the midgut lumen, bypassing the Malpighian tubules.
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
Midgut_Epithelium|Amino_Acid_Zwitterion_Equilibrium|Malpighian_Tubules
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating 'Biomolecules' (pH-dependent zwitterionic states) with 'Structural Organization in Animals' (Cockroach digestive and excretory physiology).
The primary trap is Option B, which tests the high-yield NCERT fact that the midgut (mesenteron) is NOT lined by cuticle, unlike the foregut and hindgut.
Students often compartmentalize Biochemistry and Zoology, failing to see how pH directly governs membrane transport kinetics.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Structural Organisation in Animals - Class 11 |
| Concept | Cockroach Alimentary Canal |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |