Molecular Motion

Random and erratic; reflects the kinetic energy of molecules

Velocity

Is lower in larger molecules and increases with higher temperatures

Passive Transport

Transportation and movement through the plasma membrane that is driven by concentration or pressure differences; includes diffusion, filtration, and osmosis

Active Transport

A form of facilitated diffusion that requires energy and carrier proteins that combine specifically with the transported substance; includes phagocytosis, pinocytosis, and receptor-mediated endocytosis

Diffusion

The spreading of particles in a gas or solution from high to low concentrations

Osmosis

The movement of water from low to high solute concentrations

Simple Diffusion

The unassisted diffusion of solutes through a selectively permeable membrane