Cell Signalling and Transduction
The signaling molecules called steroid hormones

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

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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

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

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Cell Signalling and Transduction
In terms of cell communication, what do bacterial pathogens such as cholera and anthrax have in common?

They destroy the receptors for key signaling molecules
They block the normal functioning of signal transduction mechanisms
They prevent the production of key signaling molecules
They alter the chemical structure of key signaling molecules

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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*?

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

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Cell Signalling and Transduction
cAMP and cGMP are derived from

ATP and GTP by the actions of guanylate cyclase and adenylate cyclase respectively
GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively
ATP and GTP by the actions of adenylate cyclase and guanylate cyclase respectively
None of these

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