Hypothesize why the pores in the cell membrane are differnt sizes?

The pores are designed to let certain molecules in/out of the cell. Thus various sizes will restrict what is allowed to pass through the membrane. The composition of the interior portion of the pore also matters - for example if it%26#039;s made up of amino acids that are negatively charged then it will better allow neutral or positively charged molecules to pass, but won%26#039;t allow negatively charged molecules to pass.|||probably to let different substances in and out.