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Question #46152

Difficulty: 8/10 | 🟢 Free

The Question

During a comparative physiological study, a mammal and a marine crustacean are exposed to severe hypercapnic (high $pCO_2$ ) and acidic conditions. Which of the following statements correctly contrasts the structural and functional responses of their respiratory pigments?

Options

A.
Mammalian hemoglobin undergoes competitive inhibition by $CO_2$ at the iron-porphyrin site, whereas crustacean hemocyanin is unaffected by $pCO_2$ changes.
B.
Mammalian hemoglobin (Fe-based) in erythrocytes unloads $O_2$ efficiently via the Bohr effect, whereas crustacean hemocyanin (Cu-based) in hemolymph loses conformational stability at its active site under severe acidification, leading to hypoxia.
C.
Both pigments utilize iron as the central metal ion, but hemoglobin is packaged in erythrocytes while hemocyanin is freely dissolved in the hemolymph.
D.
High $pCO_2$ induces a left shift in the oxygen dissociation curve for mammalian hemoglobin, but a right shift for crustacean hemocyanin.

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Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Comparative_Analysis

Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.

Concepts Behind This Question

Hemocyanin|Bohr_Effect|CO2_Partial_Pressure

Why This Question Is Tricky

Common Mistakes

Conceptual Pivot: This question tests the integration of 'Animal Kingdom' (Arthropoda characteristics: Cu-based hemocyanin dissolved in plasma) with 'Breathing and Exchange of Gases' (Bohr effect and pigment biochemistry).

A common misconception is that $CO_2$ competitively binds to the iron in heme (confusing it with Carbon Monoxide).

The question also highlights the physiological limits of the Bohr effect, contrasting vertebrate adaptation with arthropod vulnerability to extreme pH drops.

Quick Facts About This Question

Question Information

Subject	Biology
Chapter	Animal Kingdom - Class 11
Concept	Arthropoda Respiratory Diversity
Difficulty	8
Cognitive Load	5
Target Solve Time	120 sec
Access	Free