1. Take out your homework

2. Osmosis/Diffusion Osmosis/diffusion – particles move from high concentration to low concentration No energy needed It’s the ONLY way water moves

3. Osmosis/Diffusion What is meant by the terms isotonic, hypertonic and hypotonic? Use them to describe the scenario from yesterday What is osmotic pressure? How does it affect cells? 20 minutes, then I’ll check ‘em

4. Active Transport What if you want to move things against the concentration gradient? From lower concentration to higher concentration? That’s going to take energy Active Transport

5. Pumps Endocytosis Exocytosis

6. Example of Facilitated Diffusion and Active Transport How does your brain “tell” your body what to do? Neurons send messages to the peripheral nerves The message is sent by electricity (small voltage) Yep, charges

7. Example of Facilitated Diffusion and Active Transport A Neuron is a cell, so it has a membrane and proteins Na+/K+ Pumps 3 Na+ out 2 K+ in

8. Example of Facilitated Diffusion and Active Transport Membrane has pumps, but it also has channels

9. Example of Facilitated Diffusion and Active Transport What if you BLOCKED the sodium channels?

10. Passive vs Active Transport Diffusion/Osmosis = passive; NO additional energy needed Particles move from HIGH concentration to LOW Active Transport needs energy (ATP) to move particles against (“up”) the concentration gradient = LOW to HIGH Water ONLY moves by osmosis

11. Homework Written answer to Obj. 17