Question

The different classes of GPCR ligands (proteins, amino acid derivatives, or fatty acids) bind to receptors with different numbers of transmembrane domains.

A. True
B. False

Answer 1

GPCR (G-protein coupled receptor) ligands are a diverse group of molecules that bind to GPCRs and activate downstream signaling pathways. GPCRs are integral membrane proteins that span the cell membrane and have seven transmembrane domains. These domains are composed of hydrophobic amino acids that anchor the receptor within the lipid bilayer.
The ligands that bind to GPCRs can vary in their chemical structure and origin. Some GPCR ligands are proteins, such as hormones or neurotransmitters, that bind to the extracellular region of the receptor. Other ligands are small molecules derived from amino acids or fatty acids.
It is important to note that the number of transmembrane domains in GPCRs is conserved across different ligand classes. Regardless of whether the ligand is a protein, amino acid derivative, or fatty acid, the GPCR it binds to will always have seven transmembrane domains.
Therefore, the statement that different classes of GPCR ligands bind to receptors with different numbers of transmembrane domains is false. All GPCR ligands bind to receptors with seven transmembrane domains.

False

Answer 2

All G-protein-linked receptors have seven transmembrane domains, regardless of the type of ligand they bind to.

Step-by-step explanation:

All G-protein-linked receptors have seven transmembrane domains, regardless of the type of ligand they bind to. The ligands can be proteins, amino acid derivatives, or fatty acids. The number of transmembrane domains in the receptor is always the same, which is seven. However, each receptor has its own specific extracellular domain and G-protein-binding site.