Cell Signalling and Transduction
Nitroglycerin has long been administered to human patients suffering from chronic chest pain (angina). This medication works because it

is broken down into hormones that affect the heart
breaks down into nitric oxide, which increases blood flow to the heart
mimics the action of signal receptors
interferes with chemical cascades that trigger contraction of heart muscle

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

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

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

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

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Cell Signalling and Transduction
Which of the following is true about a hydrophilic signaling molecule?

It is a steroid
Its receptor is located in the cytosol of the target cell
Since it can enter the cell, it directly affects some specific cell process
It might trigger a signal cascade that causes some effect in a cell

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Cell Signalling and Transduction
The signaling molecules called steroid hormones

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

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