Cell Transport ALMOST ALL MATERIAL IN TODAY’S LECTURE WAS COVERED ON PAGES 183 – 185 (CORNELL NOTES). POWERPOINT IS ONLINE FOR REVIEW

Outline: Types of cell transport  Passive transport (no energy)  Diffusion  Facilitated Diffusion  Osmosis  Active transport (energy required)  Active Molecular Transport  Review homework  USE YOUR CORNELL NOTES DURING TODAY’S NOTES!

Review #1 from HW first On white board

Diffusion (no energy required)  What is diffusion? Discuss, be ready to share  Movement of particles across a membrane to reach equilibrium  Particles “squeeze” between lipid molecules in membrane  Time to predict:  Where will the X’s and O’s go?  No diffusion? You’d suffocate.  Oxygen diffuses from air (lungs) into your blood

Osmosis (no energy required)  What is osmosis? Discuss, be ready to share  Diffusion of water across a membrane to reach equilibrium  Water moves between lipid molecules in membrane  Often other molecules too big to move through  Time to predict:  Where will the X’s and O’s go?  Remember the time you poured salt on the slug? Osmosis killed it.  Animation:

Facilitated Diffusion (no energy required)  Movement of larger particles through a cell membrane  Move through protein channels (tunnels)  Animation Animation  Poke yourself. Feel it?  Nerve cells opened/closed protein channels to allow the chemicals to pass through, sending the signal to your brain.

Active Transport(energy required)  Active Molecular Transport  Like facilitated diffusion, but requires energy  AnimationAnimation  Move your finger. Did it work?  Only because cells actively moved glucose inside using AMT  Glucose gave cells in your finger energy to move.  No AMT, you wouldn’t have enough energy to live!

Review HW  Review #2 - #5, be ready to share  2) Water left the Elodea cells in the “salt water slide”  3) Water left the cell because it was trying to reach equilibrium. Since salt could not move, water left the inside (little salt) and moved to the outside (more salt) to make the concentrations equal.  4) Water would rush back into the cell  5) Salt water can dehydrate your cells

Types of solution in which osmosis might occur  What is an isotonic solution? Discuss, be ready to share.  Use your Cornell notes (or the textbook on your desk).  Solution outside cell is same as inside  Water moves in/out at equal rates  Who wears contacts? (solution is isotonic)

Types of solution in which osmosis might occur  What is a hypertonic solution? Discuss, be ready to share.  Solution outside cell is greater than inside (e.g. more salty)  Will water move in or out of a cell?  Water moves out of cell (yesterday’s lab!)  Animal cells shrink  Video Video  Plant cells – walls stay rigid, inside cell shrinks  Video Video  Who likes salty chips?  Cell in lip lose water, become “wrinkly”

Types of solution in which osmosis might occur  What is a hypotonic solution? Discuss, be ready to share.  Solution outside cell is less than inside (e.g. less salty)  Water moves into the cell  Animal cells expand – can lead to “lysis”  Video (start at 1 min) Video  Plants, fungi, bacteria get a little bigger but don’t lyse – why?  Cell wall – provides support that prevents breaking  This is why plants can “stand up” or come back after wilting  Osmosis: refreshing a lettuce leaf: videovideo  Penicillin and why this all matters  Penicillin breaks cells walls in bacteria – causing cells to lyse

Review  1) What do you think might happen to the size of a red blood cell if you put it in concentrated salt water?  Gets smaller!  2) What if you put a red blood cell in pure water?  Gets bigger! Explodes!