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Question #46188
The Question
During a physiological study, a lizard and a rat are exposed to acute environmental hypercapnia (elevated CO2). The lizard exhibits a much more rapid onset of severe blood acidosis than the rat. Based on the principles of circulation and gas transport, which of the following best explains this vulnerability in the lizard?
Options
- A.
The absence of the enzyme carbonic anhydrase in reptilian erythrocytes prevents the buffering of excess hydrogen ions.
- B.
Incomplete ventricular septation causes baseline systemic pCO2 to be high, leading to rapid saturation of the Hamburger phenomenon during external CO2 loading.
- C.
The complete separation of pulmonary and systemic circuits in reptiles prevents compensatory hyperventilation during hypercapnia.
- D.
Reptilian erythrocytes lack the bicarbonate-chloride carrier protein, relying entirely on the dissolved state for CO2 transport.
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
Reptilian Heart Anatomy|Chloride Shift (Hamburger Phenomenon)|Breathing and Exchange of Gases
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize 'reptiles have a 3-chambered heart' and 'chloride shift transports CO2' as isolated NCERT facts.
The trap is failing to synthesize them: incomplete double circulation means systemic blood is mixed, which inherently reduces the physiological buffering capacity (headroom) of the Hamburger phenomenon when faced with environmental hypercapnia.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Reptilian Heart Anatomy |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |