ANIMAL PHYSIOLOGY
CHEMICAL SIGNALS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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G proteins contain only one important binding site.
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When a G protein binds to an activated receptor protein, ADP is exchanged for ATP.
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G protein-linked receptors are transmembrane proteins.
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G proteins usually float free in the cytoplasm.
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Detailed explanation-1: -GPCRs are integral membrane proteins that possess seven membrane-spanning domains or transmembrane helices. The extracellular parts of the receptor can be glycosylated.
Detailed explanation-2: -Correct answer: G protein-coupled receptors contain nine seven transmembrane alpha helices. All other statements are true of G protein-coupled receptors.
Detailed explanation-3: -Which out of the following statements is true about G-protein couple receptors? Explanation: GPCR is characterized by an extracellular N-terminus and an intracellular C-terminus.
Detailed explanation-4: -Answer and Explanation: The correct answer is (b) G protein-linked receptors form dimers when activated, tyrosine kinase-linked receptors do not. G protein-linked receptors and tyrosine kinase receptors are both cell-surface signal receptors.