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Question #47478
The Question
During a study on molecular oncology, a researcher observes a human cell line exhibiting uncontrolled cell division. Transcriptomic analysis reveals continuous expression of genes normally regulated by a specific steroid hormone, despite the cells being cultured in a completely ligand-free medium. Which of the following genetic alterations best explains this phenomenon?
Options
- A.
A gain-of-function mutation in a proto-oncogene encoding an intracellular receptor, rendering it constitutively active as a transcription factor.
- B.
A loss-of-function mutation in a proto-oncogene, preventing the dissociation of the hormone-receptor complex from the DNA response element.
- C.
A gain-of-function mutation in a gene encoding adenylate cyclase, leading to continuous generation of cAMP secondary messengers.
- D.
A loss-of-function mutation in a tumor suppressor gene encoding a membrane-bound receptor, bypassing the need for extracellular ligands.
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
Nuclear_Receptor|Steroid_Hormones|Proto-oncogenes
Why This Question Is Tricky
Common Mistakes
The Conceptual Pivot lies in integrating the mechanism of hormone action (Class 11) with the molecular basis of cancer (Class 12).
Students often confuse the signaling pathways of steroid vs. peptide hormones (falling for the cAMP trap) or mix up the mutation types required for proto-oncogenes (gain-of-function) versus tumor suppressor genes (loss-of-function).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Chemical Coordination and Integration - Class 11 |
| Concept | Hormone Receptors Location |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |