Warm Up Please get out a pencil and grab a note taking sheet from the lab table

Think about it: How do you prevent unwanted materials like bugs and leaves from coming through a window? Write you answer on your note-taking sheet Answer: Window Screen

Cell Membrane Cells take in food, oxygen & other substances from their environments Cells also release waste materials into their environments The cell membrane works for a cell like a window screen does for a room. Function: It is a selectively permeable membrane that allows things to enter or leave the cell Things can move through a cell membrane in several ways

Passive Transport The movement of substances through the cell membrane without the input of energy 3 Types: Diffusion Osmosis Facilitated Diffusion

Diffusion Random movement of solutes from an area where there is more of them to where there is fewer of them. High Concentration Low Concentration The goal is to have molecules equal on both sides: aka equilibrium Once equilibrium is reached, diffusion stops

Osmosis The Diffusion of water through a cell membrane Passive Transport Osmosis and diffusion are similar, except diffusion is the movement of H20 instead of solutes.

Diffusion vs Osmosis

Facilitated Diffusion The process in which molecules can only enter and leave the cell with the help of a transport protein that is embedded in the cell membrane