A cell membrane can be modeled as a thin, impermeable layer of thickness L, pierced by tiny holes of radius, r. The combined area of all of the holes amounts to a fraction, a of the total membrane area. Assume that.

Some small dissolved solute is held at a uniform concentration ceverywhere on one side of the membrane; initially, the other side has onlypure water.

The solute molecules are much smaller than r.

a) Find the resulting initial flux of solute molecules across the membrane.
b) Suppose that a =0.1%, c=0.1M, L=4 nm and r=1 nm. What is theflux?

Evaluate your answer in molecules per square micrometer persecond.