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Question #46329
The Question
A mammalian population suffers from a respiratory pathology that significantly increases physiological dead space, while tidal volume and breathing rate remain constant. Which of the following represents the most accurate downstream consequence of this structural limitation on the organism's bioenergetics and its ecological role?
Options
- A.
Decreased alveolar pO2 limits oxygen availability at the mitochondrial matrix, directly inhibiting the enzymes of the TCA cycle and lowering secondary productivity.
- B.
Reduced alveolar ventilation limits the availability of the terminal electron acceptor at the inner mitochondrial membrane, increasing respiratory energy expenditure and decreasing net secondary productivity.
- C.
Accumulation of alveolar pCO2 induces a leftward shift in the oxygen-hemoglobin dissociation curve, compensating for the reduced pO2 by increasing tissue oxygen delivery.
- D.
The resulting cellular hypoxia increases the efficiency of oxidative phosphorylation to compensate for the low pO2, thereby increasing the biomass available for the next trophic level.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Dead Space Ventilation|Trophic Efficiency Limits|Terminal Electron Acceptor
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating Human Physiology (Dead Space/Ventilation), Cellular Respiration (Location of ETS and role of O2), and Ecology (Secondary Productivity = Gross Assimilation - Respiratory Loss).
The primary trap is Option A, which tests the exact location of oxygen utilization (Inner Membrane vs Matrix) and the distinction between direct vs indirect inhibition of the Krebs cycle.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Breathing and Exchange of Gases - Class 11 |
| Concept | Dead Space Ventilation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |