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Question #45766
The Question
Macrophages and leucocytes exhibit amoeboid movement effected by pseudopodia formation. Suppose a genetic mutation in a human macrophage causes its chemotactic receptors to remain constitutively active (failure of the receptor desensitization feedback loop) upon encountering a bacterial chemokine. Which of the following best describes the immediate physiological consequence on the cell's locomotion?
Options
- A.
It will exhibit accelerated, highly directional diapedesis towards the bacteria due to continuous receptor activation.
- B.
It will lose directional gradient sensing, resulting in chemotactic paralysis and ATP exhaustion from futile microfilament cycling.
- C.
Amoeboid movement will cease entirely because the continuous signal prevents the depolymerization of microtubules, the primary elements involved.
- D.
Cytoplasmic streaming will completely halt because the continuous signal directly inhibits the release of calcium ions from the endoplasmic reticulum.
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
Feedback_Mechanism_Loops|Pseudopodia|Hormone_Half-life
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often equate 'continuous receptor activation' with an 'enhanced cellular response' (hyperactivity).
They fail to realize that directional movement requires a gradient, which necessitates receptor desensitization to reset and sense concentration differences.
Additionally, Option C tests a high-frequency NCERT location/structure trap by swapping microfilaments (actin) with microtubules (tubulin).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Locomotion and Movement - Class 11 |
| Concept | Amoeboid Movement Mechanism |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |