Consider the cartoon of the potassium ion channel given at the right. Label the following: cell membrane, hydrophilic heads of membrane lipids, hydrophobic tails of membrane lipids, membrane-side of potassium ion channel, channel-side of the potassium ion channel. Be sure you know what the purplish balls represent in this diagram.

Figures 3A and 3B from the paper are ribbon diagrams showing a top down view and a side view of the potassium ion channel. The potassium ion channel is made up of four identical subunits ( a homotetramer)

How many a-helices comprise each protein subunit?

How many total a-helices comprise the potassium ion channel?