Before You Begin
Question #45430
The Question
Certain malignant tumors secrete a Parathyroid Hormone-related Peptide (PTHrP), leading to systemic hypercalcemia. Oncologists observe that this elevated calcium level inadvertently accelerates the metastasis of these tumor cells through the extracellular matrix. Based on the principles of cellular movement and calcium signaling, how does increased intracellular calcium mechanistically facilitate this rapid extravasation?
Options
- A.
It binds to the regulatory proteins of microfilaments, unmasking active sites and enhancing the actin-myosin contractility required for amoeboid migration.
- B.
It stimulates the sarcoplasmic reticulum of the tumor cells to release more calcium, directly polymerizing tubulin into rigid flagella for propulsion.
- C.
It acts as a secondary messenger to inhibit the secretion of extracellular proteases, thereby preserving the structural integrity of the tumor mass.
- D.
It triggers the hypersecretion of calcitonin from the thyroid gland, which acts as a chemoattractant for tumor cells to invade bone tissue.
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
Sarcoplasmic_Reticulum|Actin-Myosin|Malignant_Cell_Migration
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often restrict the role of actin-myosin contractility and calcium-dependent unmasking of active sites strictly to skeletal muscle fibers.
The trap tests their ability to extrapolate that non-muscle cellular motility (amoeboid movement of cancer cells) relies on the exact same microfilament machinery and calcium signaling for physical movement.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Chemical Coordination and Integration - Class 11 |
| Concept | Calcium Homeostasis |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |