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

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Cell Signalling and Transduction
cAMP and cGMP are derived from

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

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

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

All of these
phosphorylated proteins act with enzymes to trigger the signal cascade
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
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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