For water to travel across the cell membrane at a substantial rate the water molecules travel through protein channels known as aquaporins is what diffusion

The appropriate response is Facilitated Diffusion. It is the procedure of unconstrained detached transport of atoms or particles over a natural film by means of particular transmembrane indispensable proteins. 
In the cell, cases of atoms that must utilize facilitated diffusion to move all through the cell film are glucose, sodium particles, and potassium particles. They pass utilizing transporter proteins through the cell film without vitality along the fixation slope.

Ithink a saturated phospholipid