MCAT® ExamBiological and Biochemical Foundations of Living SystemsMedium
A patient is diagnosed with a genetic disorder caused by a defect in the gene encoding for a specific receptor protein on the surface of their cells. This defect prevents the receptor from properly binding its ligand, leading to impaired cellular signaling. This scenario primarily involves a disruption in which aspect of cell structure and function?
- ACytoskeletal integrity
- BIntracellular transport
- CSignal transduction
- DCell-cell adhesion
Show answer & explanationAnswer & explanation
Correct answer: C. Signal transduction
The binding of a ligand to a receptor initiates a cascade of events known as signal transduction, which transmits the external signal into the cell. A defect preventing ligand binding directly impairs this process.
Why the other options are wrong
- A. Cytoskeletal integrity relates to the cell's shape and internal organization, not directly to receptor-ligand binding.
- B. Intracellular transport involves movement of molecules within the cell, not the initial reception of external signals.
- D. Cell-cell adhesion involves cells sticking together, which is a different function from a receptor binding its specific ligand for signaling.
Signal Transduction
The process by which a cell converts an extracellular signal into an intracellular response, typically involving a series of molecular events (pathway).
- Begins with ligand binding to a receptor.
- Amplifies and diversifies signals.
- Crucial for cell growth, differentiation, and metabolism.
Memory trick: Signals Transduce: Receive, Relay, Respond.