Passive Transport Across the Cell Membrane Examples Diffusion

Passive. Transport Across the Cell Membrane Examples: Diffusion and Osmosis

Define Diffusion �The movement of molecules from an area of high concentration to an area of low concentration �Concentration Gradient �The difference in concentration between two places http: //highered. mcgrawhill. com/sites/00724958 55/student_view 0/chapt er 2/animation__how_dif fusion_works. html

Draw the Diagram of the Diffusion Example That Was Presented in Class

So, What Does This Mean to a Cell? �http: //www. youtube. com/watch? v=EFDq 66 sg. BK 0 �Cells can have materials diffuse into them � OR �Cells can have materials diffuse out of them

Osmosis is simply the diffusion of water Water will move from an area of high concentration to an area of low concentration �http: //www. youtube. com/wa tch? v=4 Jy. T__Dea 8 Q Add salt water to the area surrounding the cell – Water diffuses out of the cell and the cell shrinks – �Normal Red onion Cell Identify the cell wall and cell membrane

Another Osmosis Example �This shows what happens to red blood cells in both distilled (100%) water and salt water. The normal H 2 O concentration for the cells is about 99% water

A Look at What’s Happening at the Cell Membrane During Osmosis Only certain things can “fit” through the pores on the cell membrane �Before Osmosis After Osmosis

Molecules that can diffuse 1. Water (H 2 O) 2. Carbon Dioxide (CO 2) 3. Glucose (C 6 H 12 O 6) The molecules that are small enough to fit through the pores of the cell membrane can diffuse into and out of the cell