Cell Signalling and Transduction
Which of the following statements about G proteins is false?

They are involved in signal cascades
They bind to and are regulated by guanine nucleotides
They become activated when bound to GDP
They must be active before the cell can make needed cAMP

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

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Cell Signalling and Transduction
When a __________ reaches its __________ , there is a specific means of receiving it and acting on the message. This task is the responsibility of specialized proteins called __________ .

signaling molecule; target cell; receptors
signaling molecule; target cell; G proteins
kinase; receptor; proteases
signaling molecule; receptor; G proteins

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

All of these
receptor kinases play a key role in triggering the signal cascade
the signaling molecule binds to a surface receptor
phosphorylated proteins act with enzymes to trigger the signal cascade

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