THE CELL
CELL COMMUNICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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are found only in animal cells, and only embedded in or located just beneath the cellʹs membrane.
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are found only in bacterial cells, embedded in the cellʹs plasma membrane only.
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are thought to have evolved very early, because of their similar structure and function in a wide variety of modern organisms.
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Detailed explanation-1: -G protein coupled receptors (GPCRs) are integral membrane proteins that are used by cells to convert extracellular signals into intracellular responses, including responses to hormones, neurotransmitters, as well as responses to vision, olfaction and taste signals.
Detailed explanation-2: -(A) GPCRs contain seven transmembrane helices (gray), three extracellular loops (ECLs) and an amino terminus (orange), and three intracellular loops (ICLs) and a carboxyl terminus (purple). The transmembrane domain consists of the transmembrane helices, as well as the extracellular and intracellular loops.
Detailed explanation-3: -G protein-coupled receptor (GPCR), also called seven-transmembrane receptor or heptahelical receptor, protein located in the cell membrane that binds extracellular substances and transmits signals from these substances to an intracellular molecule called a G protein (guanine nucleotide-binding protein).
Detailed explanation-4: -G protein-coupled receptors (GPCRs) comprise the largest protein superfamily in mammalian genomes. They share a common seven-transmembrane topology and mediate cellular response to a variety of extracellular signals ranging from photons and small molecules to peptides and proteins (1).