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Question #47477
The Question
A child presents with severe ataxia, characterized by a profound loss of spatial coordination and balance. MRI reveals a malignant tumor (Medulloblastoma) originating from the rapidly dividing external granular layer of the hindbrain. Based on the principles of molecular oncology and neural control, which of the following statements best explains the pathogenesis of this condition?
Options
- A.
A gain-of-function mutation in a tumor suppressor gene caused a loss of contact inhibition, leading to a mass that disrupts the cerebral motor cortex.
- B.
The activation of cellular oncogenes (c-onc) into oncogenes led to a hyper-proliferative mass that physically displaces the cerebellar neural circuits.
- C.
The inactivation of proto-oncogenes resulted in uncontrolled cell division, chemically degrading the neurotransmitters required by the medulla oblongata.
- D.
The loss of contact inhibition due to proto-oncogene activation primarily compressed the medulla oblongata, causing the loss of voluntary motor coordination.
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
Cerebellum|Medulloblastoma|Cell Cycle|Cellular Proliferation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: This question tests two distinct NCERT concepts simultaneously: the molecular basis of cancer (activation of proto-oncogenes vs. inactivation of tumor suppressor genes) and the functional anatomy of the brain.
The primary trap is confusing the activation/inactivation states of cancer-related genes and misattributing the symptom of ataxia to the cerebrum or medulla instead of the cerebellum.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Neural Control and Coordination - Class 11 |
| Concept | Cerebellar Coordination Dynamics |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |