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Question #46704

Difficulty: 8/10 | 🟢 Free

The Question

A frog relying solely on cutaneous respiration during hibernation is exposed to a metabolic toxin that specifically and competitively inhibits Complex IV (Cytochrome c oxidase) of the mitochondrial Electron Transport System. Despite a perfectly healthy, moist skin surface and a high atmospheric $pO_2$ , the net inward diffusion of oxygen across the frog's skin eventually halts. Which of the following best explains this physiological phenomenon?

Options

A.
The resulting anaerobic respiration produces excess lactic acid, which lowers blood pH and completely halts the diffusion of gases across the skin.
B.
The cessation of terminal electron acceptance prevents $O_2$ consumption, causing tissue $pO_2$ to rise and abolish the diffusion gradient.
C.
The inhibition of Complex IV directly alters the allosteric properties of hemoglobin, preventing it from loading $O_2$ at the cutaneous capillary bed.
D.
The toxin induces severe vasoconstriction in the cutaneous capillary bed, physically blocking the gaseous exchange interface.

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

Frog Integumentary Respiration|Terminal Electron Acceptor|Chemiosmotic ATP Yield

Why This Question Is Tricky

Common Mistakes

Conceptual Pivot: Integrating 'Breathing and Exchange of Gases' with 'Cellular Respiration'.

Students often fail to realize that the physical diffusion gradient at the respiratory surface (macro-level) is entirely dependent on the biochemical consumption of oxygen at the terminal end of the Electron Transport System (micro-level).

A healthy respiratory surface is useless without a metabolic 'sink' to maintain the gradient.

Quick Facts About This Question

Question Information

Subject	Biology
Chapter	Structural Organisation in Animals - Class 11
Concept	Frog Integumentary Respiration
Difficulty	8
Cognitive Load	5
Target Solve Time	120 sec
Access	Free