Cell Signalling and Transduction
In paracrine signaling, the signaling molecules affects only

both (a) and (b)
None of these
target cells close to the cell from which it was secreted
target cells distant from its site of synthesis in cells of an endocrine organ

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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 alter the chemical structure of key signaling molecules
They block the normal functioning of signal transduction mechanisms
They prevent the production of key signaling molecules
They destroy the receptors for 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 nitric oxide breaks down quickly and thus cannot travel far
None of these
Because nitric oxide cannot cross cell membranes and enter the blood
Because other body tissues use a different signaling molecule

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Cell Signalling and Transduction
The signaling molecules called steroid hormones

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

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

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