F A C T O R S A F F E C T I N G T H E R A T E O F D I F F U S I O N

CELL MEMBRANE

Summary of Membrane Transport

Diffusion of Nonelectrolytes

Simple diffusion

Concentration Gradient (CA − CB)

Partition Coefficient (K)

Solubility of a solute in oil relative to its solubility in water

Diffusion Coefficient (D)

Size of the solute molecule

Viscosity of the medium

Thickness of the Membrane (ΔX)

The thicker the cell membrane, the lower the rate of diffusion.

Surface Area (A)

The greater the surface area of membrane available, the higher the rate of diffusion

Diffusion of Electrolytes

Facilitated Diffusion

Primary Active Transport

Secondary Active Transport

Cotransport

Countertransport

Saturation

Carrier proteins have a limited number of binding sites for the solute

Stereospecifity

The binding sites for solute on the transport proteins are stereospecific

Competition

Chemically related solutes can be recognized, bound, and get transport, thereby occupying some of the binding sites of other solutes

Reference:

Costanzo Physiology 5th edition