MCAT Basics (from MedSchoolCoach) Biosignaling
Jun 19, 2025
Explore the fascinating world of biosignaling as cells communicate through mechanisms like voltage-gated and ligand-gated ion channels. Discover how these channels play crucial roles in neuronal signaling and muscle contraction, debunking common misconceptions along the way. Delve into enzyme-linked receptors, particularly receptor tyrosine kinases, and their links to growth and cancer. Lastly, learn about G-protein coupled receptors and the role of secondary messengers like cAMP in cellular processes.
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Stimulus → Process → Response Framework
- Biological responses follow the pattern: stimulus, internal processing, and response.
- This framework applies across systems from fight-or-flight to transcription regulation.
How Voltage-Gated Channels Propagate Signals
- Voltage-gated ion channels open in response to local membrane potential changes and propagate depolarization sequentially.
- Each channel is usually specific to one ion type and opens to let that ion flow down its gradient.
Electrical To Chemical Switch At Terminals
- When depolarization reaches the axon terminal, calcium channels open and convert the electrical signal into a chemical one.
- Neurotransmitters are released to signal the next cell or effector structure.