Cells are constantly exchanging materials—nutrients, waste, signals—with their environment. The cell membrane is a dynamic barrier that controls this exchange. In this webquest, you will explore how substances cross the membrane by different methods: passive (diffusion, facilitated diffusion, osmosis) and active (pumps, vesicle transport). You will watch an Amoeba Sisters video to build your foundation, read a short informational article, and then interact with the PhET Membrane Channels simu