PASSIVE TRANSPORT S7L2: Students will describe the structure and function of cells, tissues, organs, and organ systems. a. Explain that cells take in nutrients in order to grow and divide and to make needed materials.

How do cells grow and divide? The cells take in nutrients and other need materials.

How do materials enter or exit the cell? Through the cell membrane   The cell membrane is semi-permeable -Certain materials can enter and others can not

What is another example of semi-permeable Screen door (Lets in air, but keeps out insects)

Two ways materials enter or exit the cell? Passive and Active Transport Active = Requires Energy Passive = No Energy

What is passive transport? The movement of substances through the cell membrane without the input of energy. Two Examples: Diffusion and Osmosis

What is diffusion? Random movement of molecules from an area where there is relatively more of them into an area where there is relatively fewer In other words, random movement from areas of high concentration to areas of low Diffusion will occur until equilibrium is reach (equal number of molecules in both areas)

What is osmosis? The diffusion of water through a cell membrane