Notice these cells on their membranes contain these special protein receptors that can actually bind these Morphins, these special signal molecules. Notice on the left side we have a much higher concentration of these morphogens than on the right side. And because we have many more of these mortgagen molecules around this cell these signal molecules will be much more likely to actually bind onto the receptor protein than on this cell. And so the different types of processes that takes place inside this cell will be different than inside this cell as a result of the binding of that mortgagen onto the protein cell receptor on that membrane. Now, the question is what usually happens when the mortgagen actually binds onto that protein receptor? So when the binding takes place usually a type of molecule known as a transcription factor is activated inside that cell.