And To Generalize The Structure Of An Ion channel, we're Going To Focus On A Specific Type Of ion channel known as The Potassium Ion channel. So The Potassium ion channel allows the movement Of Potassium Ions across The Membrane, down Their electrochemical, grading From A High Electric chemical Potential to A Low Electric chemical potential. Now, the structure of potassium ion channels basically consists of four individual and identical polypeptide chains. And each one of these subunits, each one of these chains looks like this. So we basically have these three domains. Three alpha helices one shown in brown, one shown in dark purple, one shown in light purple.