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Question #45601
The Question
A diploid somatic cell possesses two distinct mutant alleles for a proto-oncogene that codes for a membrane-bound growth factor receptor. Both mutant receptors are simultaneously expressed on the cell surface, creating a hyper-active signaling cascade that induces rapid metastasis. Which of the following statements is INCORRECT regarding this cellular event?
Options
- A.
The simultaneous expression of both distinct mutant receptors on the cell membrane is a molecular manifestation of co-dominance.
- B.
The transition to a metastatic state requires the loss of contact inhibition, a regulatory property inherent to normal cells.
- C.
This transformation is driven by a recessive loss-of-function mutation, as both alleles must be mutated to bypass the G1/S checkpoint.
- D.
The mutant alleles act as oncogenes, providing continuous proliferative signals that render internal cell cycle checkpoints ineffective.
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
Cell_Signaling|Gene_Expression|Tumor_Suppression
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between the mutational mechanisms of Proto-oncogenes (dominant, gain-of-function) and Tumor Suppressor Genes (recessive, loss-of-function).
The trap lies in the premise stating 'two mutant alleles' are present.
Students often reflexively associate 'two mutated alleles' with the recessive two-hit hypothesis of tumor suppressors, ignoring the prompt's explicit description of a 'hyper-active' (gain-of-function) receptor and 'co-dominant' expression.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Principles of Inheritance and Variation - Class 12 |
| Concept | Co-dominance Allelic Interaction |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |