How does the size of molecular pores in a membrane affect diffusion?

Question

How does the size of molecular pores in a membrane affect diffusion?

Answer 1

Water (as a polar molecule) cannot pass through the membrane on its own.  It must use special pores built with proteins known as aquaporins.  Since diffusion is reliant on the movement of water, the rate of water through these special pores control diffusion.  Therefore diffusion is not automatic, nor immediate.  The number of pores in the membrane can reduce or increase the rate of diffusion.

Answer 2

The pores allow only molecules smaller than their pore sizes to pass through.

Answer 3

From what I remember, the size of molecular pore in a membrane affects diffusion by limiting the flow of molecules into and out of the cell. For example if the pore was the size of this o then only water can go through not a tennis ball.