Cell membranes protect and organize cells. All cells have an outer plasma membrane that regulates not only what enters the cell, but also how much of any given substance comes in. Unlike ...

Endocytosis occurs when the cell membrane engulfs particles (dark blue) outside the cell, draws the contents in, and forms an intracellular vesicle called an endosome. This vesicle travels through ...

This takes place when molecules diffuse across the cell membrane by travelling through specific transport proteins. It occurs down a concentration gradient - molecules move from an area of high to ...