📡 Signal Transduction – Receptors, Cascades & Second Messengers
Cell communication is a foundational biology topic on the DAT. Questions often test your understanding of how signals are received and amplified inside cells.
Today’s breakdown includes:
Signal transduction basics
Receptors (G-protein, tyrosine kinase, etc.)
Second messengers (cAMP, IP₃, Ca²⁺)
DAT-style questions and mnemonics
🔐 Types of Receptors on the DAT
| Receptor Type | Description | Example Ligands |
|---|---|---|
| G-protein coupled receptor (GPCR) | Activates internal G-protein signaling | Epinephrine, glucagon |
| Receptor tyrosine kinase (RTK) | Dimerizes and autophosphorylates | Insulin, growth factors |
| Ion channel-linked receptor | Opens/closes in response to ligands | Acetylcholine, GABA |
🧠 GPCRs = most frequently tested receptor type
🌊 Second Messengers: The Cell’s Internal “Echo”
| Messenger | Role |
|---|---|
| cAMP | Activates protein kinase A (PKA) |
| IP₃ | Releases Ca²⁺ from ER |
| Ca²⁺ | Triggers secretion, muscle contraction |
| DAG | Activates protein kinase C (PKC) |
✅ These molecules amplify the signal from 1 receptor into 1000+ reactions.
📈 DAT-Style Practice Question
Q: A hormone binds a GPCR and increases cAMP levels. What enzyme is activated next?
A: Protein kinase A (PKA)
🎯 DAT Strategy Tips
✅ Know which receptors use G-proteins vs kinase activity
✅ Learn common second messengers (especially cAMP)
✅ Memorize “amplification” concept—1 ligand → big intracellular response
✅ Practice reading diagrams and pathway logic
Visual learning? Reinforce at kingofthecurve.org/studyscience
🚀 Call-to-Action
Want to amplify your DAT score?
Download the KOTC App and access:
Signal transduction flashcards
Interactive receptor pathway quizzes
Curve Coin system to track your mastery
Animated visuals of each step in the cascade
⚡ Unlock the signal to success—with KOTC.
Frequently Asked Questions (FAQs)
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Aim for 4-6 focused hours, ensuring you incorporate breaks to avoid burnout.
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Practice mindfulness techniques, take practice exams under realistic conditions, and maintain a balanced lifestyle.
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Set short-term goals, seek support from mentors, and reward yourself for small achievements.
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Regular exercise improves focus, reduces stress, and enhances overall mental clarity.
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KOTC offers personalized learning tools, gamification features, and adaptive question banks to help students stay on track without burnout.
