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Question #47442
The Question
The eyes of cephalopods and mammals represent analogous organs. In normal mammalian phototransduction, light induces the dissociation of retinal from opsin, altering membrane permeability and causing hyperpolarization. In contrast, invertebrate photoreceptors depolarize upon light stimulation. If a mammalian rod cell undergoes a mutation that alters its cascade to perfectly mimic the invertebrate mechanism, what would be the immediate physiological consequence upon exposure to light?
Options
- A.
The rod cell will depolarize, generating an action potential that is transmitted directly to the visual cortex.
- B.
The rod cell will depolarize, resulting in an increased exocytosis of the neurotransmitter glutamate to the bipolar cells.
- C.
The rod cell will hyperpolarize, leading to a decreased release of glutamate and subsequent activation of ganglion cells.
- D.
The rod cell will depolarize, causing the continuous efflux of K+ ions to maintain the 'dark current' in the presence of light.
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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
Cephalopod_Eye|Vertebrate_Retina|Hyperpolarization
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: This question tests two major concepts simultaneously.
First, the physiological rule that cellular depolarization universally triggers neurotransmitter exocytosis.
Second, a strict NCERT detail trap: students often assume all neurons fire action potentials, but NCERT explicitly states that in the retina, action potentials are generated in the ganglion cells, while photoreceptors and bipolar cells only produce graded potentials.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Neural Control and Coordination - Class 11 |
| Concept | Retina Phototransduction Cascade |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |