Transport across cell membranes Which type of transport requires ATP? Why? Which type of transport requires carrier proteins? Passive transport Diffusion Facilitated Diffusion What is transported? What is transported? How does it happen? How does it happen? Proteins in the cell membrane are often involved in transport across the membrane. Channel proteins provide channels for ions to diffuse through. Carrier proteins interact with the molecule being transported. A B C What do the diagrams show? A B C D D