Re: How does a cell recive information and how does it process the information?

Dear Natalie,

Thanks for asking the challenging question.

There is still a lot we do not know about cell information pathway.  But we do know
a bit to make this a nice story.  Usually, on the cell surface, i.e., the cell 
membrane, there are a lot of proteins playing the role as receptors of specific
molecules.  Information, often comes in the form of a small molecule traveling to 
the cell that it would like to inform.  The receptor on the membrane thus binds 
to the small information molecule and then try to make out the information.  There
are a lot of possible routes.  Two of the most plausible and impressive ones are
the following ones.

First, the molecule might actually be brought in by the receptor, in this case, 
also a transporter.  The information molecule then comes into the cell to bind to
the target protein which will really respond to the information by changing its
conformation, say from an active state to an inactive state, or vice versa.

Second, the famous second-signal system model.  It believes that some information 
molecule is not brought into the cell.  Instead, it stimulates the enzyme on the
membrane, which will then turn another small molecule in the cell (say, ATP) to 
a different one (cAMP in this case).  This product then acts as the signal to 
stimulate other functional proteins in the cell.

If you have further questions, don't hesitate to contact us.

Cheng Huang