Question

question 8
1 pts
question: which type of receptor undergoes a conformational change upon ligand binding and activates intracellular signaling cascades?
ionotropic receptor
g - protein - coupled receptor
nuclear receptor
tyrosine kinase receptor
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Explanation:

To solve this, we analyze each receptor type:

• Ionotropic receptor: Ligand binding causes ion channel opening, not mainly for intracellular signaling cascades activation via conformational change in the way the question asks.
• G - protein - coupled receptor (GPCR): When a ligand binds to a GPCR, it undergoes a conformational change. This change allows it to interact with and activate G - proteins, which then initiate intracellular signaling cascades.
• Nuclear receptor: These are located in the nucleus (or cytoplasm and then translocate to the nucleus) and bind ligands to regulate gene transcription, not the typical membrane - bound receptor that activates intracellular signaling cascades immediately upon ligand binding in the way described.
• Tyrosine kinase receptor: Ligand binding causes dimerization and autophosphorylation, but the primary conformational change and signaling initiation mechanism is different from the description (more about kinase activation through dimerization rather than the general conformational change leading to G - protein - like signaling cascades).

So the G - protein - coupled receptor is the one that undergoes conformational change upon ligand binding and activates intracellular signaling cascades.

Answer:

B. G - protein - coupled receptor