Answer-the types of transport protein in the membrane
Due to presence of hydrophylic and hydrophobic nature of the plasma memebranr;
Cretain subtances are restricted from passing through the membrane.
In order for them to gain entry into thr cystosol,specific transmembrane proteins are embedded into the rmembrane.
These memebrane proteins channels allowr the passage of Polar Solutes accross the membranes.
For example the movements of glucose and insulin accros the membrane is by special protein channels or transpoter
.
Because of their polarity,and large molecular sizes they can not pass through the cell memebrane with these transmemebrane proteins.
However, smalle molecular size polar molecuels Oxygen,ammonia pass easily.
