In  reception, a signal molecule binds to a
   receptor protein, causing it to change shape.
<P>
<BR><LI> intracellular receptors
<BR><LI> membrane receptors:+ G-protein-linked receptors+ receptor tyrosine kinases
<li> ion channel receptors
<P>
   Review:  <A ClAsS=ACT Href="http://media.pearsoncmg.com/bc/bc_campbell_biology_7/media/activities/load.html?11&amp;B" oNClick="popact('http://media.pearsoncmg.com/bc/bc_campbell_biology_7/media/activities/load.html?11&amp;B');txtcolor('reception5','gray');return false;" Id=reception5><iMg sRc="/images/tutorial.gif" aLt='' boRDer=0></A>