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 must be active before the cell can make needed cAMP
They become activated when bound to GDP

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

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

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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 alter the chemical structure of key signaling molecules
They prevent the production of key signaling molecules

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

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