Cell Signalling and Transduction
Why is it that inhaling nitric oxide reduces blood pressure only in the lung tissue and not elsewhere in the body*?

None of these
Because nitric oxide cannot cross cell membranes and enter the blood
Because nitric oxide breaks down quickly and thus cannot travel far
Because other body tissues use a different signaling molecule

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

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

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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
All of these
Smooth muscle cells could not be made to relax

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Cell Signalling and Transduction
A cell is known to respond to a particular signaling molecule. Which of the following must be true of this cell?

It is in the heart muscle
It is also the site of production for the signaling molecule
It contains the receptor for the signaling molecule
It is incapable of signal transduction

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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 intracellular signaling molecules called second messenger
decrease in the concentration of certain extracellular signaling molecules called first 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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Cell Signalling and Transduction
Nitroglycerin has long been administered to human patients suffering from chronic chest pain (angina). This medication works because it

is broken down into hormones that affect the heart
breaks down into nitric oxide, which increases blood flow to the heart
interferes with chemical cascades that trigger contraction of heart muscle
mimics the action of signal receptors

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