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

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
They become activated when bound to GDP

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Cell Signalling and Transduction
If a disease of the blood vessels caused the endothelial cells of the vessel to die, what effect would that have on the cellular activities associated with vasodilation?

Nitric oxide would no longer be produced
It would be more difficult to increase blood flow and reduce blood pressure
Smooth muscle cells could not be made to relax
All of these

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

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

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Cell Signalling and Transduction
The signaling molecules called steroid hormones

are made in one location of the body but have their effects some distance away
bind to cell surface receptors to trigger chemical cascades
never enter the blood of humans
are hydrophilic and so cannot penetrate the plasma membrane

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