Open Question
Some hormones act bya. increasing the synthesis of enzymes,b. converting an inactive enzyme into an active enzyme,c. affecting only specific target organs,d. all of these.
16. The Endocrine System
Membrane Bound Receptors and Secondary Messengers
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What is the role of G proteins in GPCR signaling?
A
Catalyzing DNA synthesis.
B
Initiating apoptosis.
C
Transcription of mRNA.
D
Activating downstream effectors.
Verified step by step guidance1
Understand that GPCR stands for G Protein-Coupled Receptor, which is a large family of cell surface receptors that respond to various external signals.
Recognize that G proteins are intracellular proteins that bind guanosine triphosphate (GTP) and guanosine diphosphate (GDP) and are involved in transmitting signals from GPCRs to other parts of the cell.
When a ligand binds to a GPCR, it causes a conformational change in the receptor, which then activates the associated G protein by facilitating the exchange of GDP for GTP on the G protein.
The activated G protein, now bound to GTP, dissociates into its subunits (usually the alpha subunit and the beta-gamma dimer), which then interact with various downstream effectors such as enzymes or ion channels, leading to a cellular response.
The role of G proteins in GPCR signaling is to act as molecular switches that activate downstream effectors, thereby propagating the signal initiated by the ligand binding to the GPCR.
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