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Question #47445
The Question
A patient presents with a genetic syndrome causing both severe night blindness and vestibular-auditory ataxia. The defect impairs the primary signal transduction mechanisms in both the retina and the inner ear. Which of the following statements correctly contrasts the normal physiological transduction in these two sensory systems?
Options
- A.
Light causes depolarization in rods by opening Na+ channels, whereas mechanical bending of stereocilia causes hyperpolarization in hair cells.
- B.
Photoreceptors directly generate action potentials upon illumination, whereas cochlear hair cells only generate graded receptor potentials.
- C.
Light induces structural changes in opsin leading to hyperpolarization of photoreceptors, whereas bending of stereocilia against the tectorial membrane opens ion channels leading to depolarization of hair cells.
- D.
Both retinal rods and vestibular hair cells rely on G-protein coupled receptors that activate secondary messengers to open Ca2+ channels.
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
Rhodopsin|Hair Cell Stereocilia|Cerebellum
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume all sensory receptors depolarize upon stimulation.
The retina is a unique exception where the stimulus (light) causes hyperpolarization (closure of channels), whereas mechanoreceptors in the ear follow the standard depolarization model via mechanically-gated channels.
Option B exploits the common misconception that photoreceptors fire action potentials directly.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Neural Control and Coordination - Class 11 |
| Concept | Cochlear Frequency Coding |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |