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

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

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

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Cell Signalling and Transduction
If a disease of the blood vessels caused the endothelial cells of the vessel to die, what effect would that have on the cellular activities associated with vasodilation?

It would be more difficult to increase blood flow and reduce blood pressure
Nitric oxide would no longer be produced
Smooth muscle cells could not be made to relax
All of these

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Cell Signalling and Transduction
Self-phosphorylation is an excellent mechanism for triggering specific catalytic function of the proteins involved in signal cascades because it

changes the shape and thus the enzymatic activity of the proteins involved
None of these
makes the receptor more likely to capture the signaling, molecule
allows hydrophilic signaling molecules to cross the plasma membrane

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Cell Signalling and Transduction
The signaling molecules called steroid hormones

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

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