Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

12. Biosignaling

Inhibitory Adenylate Cyclase GPCR Signaling

Biochemistry

12. Biosignaling

Inhibitory Adenylate Cyclase GPCR Signaling

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Multiple Choice

How does GPCR termination differ from GPCR desensitization?

GPCR termination promotes GPCR signaling while GPCR desensitization overexpresses the GPCR.

GPCR desensitization involves degradation of the GPCR while GPCR termination promotes GTPase activity of G_α.

GPCR termination blocks the GTPase activity of G_α while GPCR desensitization promotes ligand binding.

GPCR termination resets the signaling pathway in the absence of ligand, whereas GPCR desensitization dampens the cell response even in the presence of ligand.

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Verified step by step guidance

Understand the role of GPCRs (G-protein coupled receptors) in cell signaling. They are activated by ligands and initiate a cascade of intracellular events.

GPCR termination refers to the process that resets the signaling pathway. This occurs when the ligand is no longer present, and involves the promotion of GTPase activity of the Gα subunit, converting GTP to GDP, thus inactivating the G-protein.

GPCR desensitization is a mechanism that reduces the receptor's responsiveness to continuous or repeated stimulation by a ligand. This can occur even when the ligand is still present, often through receptor phosphorylation and binding of arrestin proteins.

Compare the two processes: Termination is about stopping the signal when the ligand is absent, while desensitization is about reducing the signal even when the ligand is present.

Consider the physiological implications: Termination ensures that signaling pathways are reset for future activation, while desensitization prevents overstimulation and potential cellular damage from continuous signaling.