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
never enter the blood of humans
are made in one location of the body but have their effects some distance away

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

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