Before You Begin
Question #46834
The Question
While both the lenticels of a woody dicot stem and the alveoli of a mammalian lung facilitate gaseous exchange via simple diffusion, mammalian lungs can maintain a consistently steep partial pressure gradient for O2 even during high metabolic demand. Which of the following best explains the physiological limitation of lenticels compared to alveoli in this context?
Options
- A.
Lenticels lack a convective fluid transport system and active ventilation to continuously remove diffused gases and replenish the gradient.
- B.
The complementary cells within lenticels are heavily suberized and tightly packed, creating a thicker diffusion boundary than the alveolar epithelium.
- C.
Mammalian alveoli can switch to active transport of O2 during peak metabolic demand, whereas lenticels are restricted to passive diffusion.
- D.
Lenticels depend on the counter-current flow of xylem sap to transport gases, which is significantly slower than the pulmonary capillary network.
Check Your Answer
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
Lenticels|Stomata|Breathing_Exchange_Gases
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between the 'mechanism' of gas exchange (simple diffusion in both) and the 'maintenance' of the diffusion gradient.
Students often memorize that lenticels are for gas exchange but fail to integrate the anatomical fact that complementary cells are unsuberized parenchyma (eliminating the common trap in Option B) and the physiological fact that animals use perfusion/ventilation to actively maintain steep gradients, a homeostatic feature plants completely lack.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Anatomy of Flowering Plants - Class 11 |
| Concept | Lenticels vs Stomata |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |