Cell Signalling and Transduction
Which of the following statements about G proteins is false?

They become activated when bound to GDP
They are involved in signal cascades
They must be active before the cell can make needed cAMP
They bind to and are regulated by guanine nucleotides

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Cell Signalling and Transduction
In the signal transduction mechanism known as protein phosphorylation

phosphorylated proteins act with enzymes to trigger the signal cascade
All of these
receptor kinases play a key role in triggering the signal cascade
the signaling molecule binds to a surface receptor

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Cell Signalling and Transduction
A signal cascade induced by adrenaline or thyroxine

results in the activation of a sequence of enzymes needed for the cell effect
must begin with receipt of the signal molecule by a surface receptor
All of these
involves the activation of a G protein

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Cell Signalling and Transduction
The binding of ligands to many G-proteins linked receptors leads to shortlived

decrease in the concentration of certain extracellular signaling molecules called first messenger
decrease in the concentration of certain intracellular signaling molecules called second messenger
increase in the concentration of certain extracellular signaling molecules called first messenger
increase in the concentration of certain intracellular signaling molecules called second messenger

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