Cell Signalling and Transduction
Which of the following comes under the category of cell surface receptor?

G protein linked receptors
All of these
Enzyme linked receptors
Ion-channel linked receptors

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Cell Signalling and Transduction
The signaling molecules called steroid hormones

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

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

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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
The binding of ligands to many G-proteins linked receptors leads to shortlived

decrease in the concentration of certain extracellular signaling molecules called first messenger
decrease in the concentration of certain intracellular signaling molecules called second messenger
increase in the concentration of certain intracellular signaling molecules called second messenger
increase in the concentration of certain extracellular signaling molecules called first messenger

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

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