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

G protein-Coupled Receptors

Biochemistry

12. Biosignaling

G protein-Coupled Receptors

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Multiple Choice

G protein-coupled receptors (GPCRs) are transmembrane proteins with ligand binding sites on the extracellular side of the membrane (near its N-terminal). What is the role of the G-protein in the GPCR signaling pathway?

G proteins phosphorylate GPCRs.

G proteins bind extracellular ligands and facilitate the transport into the cell.

G proteins activate enzymes that transduce the signal throughout the cell.

G proteins activate transcription of genes.

G proteins facilitate dimerization of receptor monomers.

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Verified step by step guidance

Understand the structure and function of G protein-coupled receptors (GPCRs). GPCRs are a large family of cell surface receptors that respond to various external signals. When a ligand binds to a GPCR, it undergoes a conformational change.

Recognize the role of G proteins in the GPCR signaling pathway. G proteins are intracellular proteins that interact with GPCRs. They are heterotrimeric, consisting of alpha (α), beta (β), and gamma (γ) subunits.

Identify the process of signal transduction. Upon ligand binding to the GPCR, the receptor activates the associated G protein by promoting the exchange of GDP for GTP on the alpha subunit.

Explore the downstream effects of G protein activation. The activated G protein can then interact with other intracellular targets, such as enzymes or ion channels, to propagate the signal within the cell.

Conclude with the specific role of G proteins in the signaling pathway. G proteins primarily activate enzymes that generate second messengers, which further transduce the signal throughout the cell, leading to a physiological response.