ANIMAL PHYSIOLOGY
CHEMICAL SIGNALS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A change occurs in intracellular ion concentration.
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The receptors open and close in response to protein signals.
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A change occurs on only one membrane surface:exterior or interior.
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The receptor preferentially binds with lipid or glycolipid signal molecules
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The receptor changes conformation after binding with signal polypeptides.
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Detailed explanation-1: -G-protein coupled receptors are usually found in the plasma membrane. The receptor binds a ligand from outside the cell. This binding causes a conformational change in the receptor such that the conformation of the cytoplasmic face of the receptor is altered.
Detailed explanation-2: -Answer and Explanation: When a membrane protein receptor is activated, the receptor will undergo a conformational change following The binding of the particular signal ligand.
Detailed explanation-3: -EGF is also a monomeric factor, but each molecule binds to a single receptor molecule, causing a conformational change that promotes direct binding of two ligand-bound receptors (Fig.
Detailed explanation-4: -Upon activation by a ligand, the receptor binds to a partner heterotrimeric G protein and promotes exchange of GTP for GDP, leading to dissociation of the G protein into and subunits that mediate downstream signals. GPCRs can also activate distinct signaling pathways through arrestins.
Detailed explanation-5: -Signal transduction occurs as a result of a ligand binding to the outside region of the receptor (the ligand does not pass through the membrane). Ligand-receptor binding induces a change in the conformation of the inside part of the receptor, a process sometimes called “receptor activation".