This takes place when molecules diffuse across the cell membrane by travelling through specific transport proteins ... of ATP inside the cell. This diagram shows molecules moving from area ...

Transport of molecules within a cell and out of the cell requires a complex endomembrane system. Endocytosis occurs when the cell membrane engulfs particles (dark blue) outside the cell ...

Scientists who model membrane structure and dynamics describe ... Thanks to membrane barriers and transport proteins, the cell can accumulate nutrients in higher concentrations than exist in ...