1. Bellwork ► What happens to an animal cell when it is in a hypotonic solution? ► What happens to an animal cell when it is in hypertonic solution? What about a plant cell?

2. Review ► Onion cell plasmolysis Onion cell plasmolysis Onion cell plasmolysis

3. More Review

4. Facilitated diffusion

5. Active transport and Cell signaling

6. Active Transport Active Transport ► Uses energy to pump molecules against their concentration gradient ► Where do you think they get this energy? ► ATP!!!

7. Electrical gradient ► Uneven distribution of ions gives it an electrical gradient (neg inside the cell, pos outside the cell)

8. Cotransport ► A solute flows with another substance that is diffusing across the membrane

9. EndocytosisEndocytosis - Endocytosis ► Phagocytosis – Cell eating ► Pinocytosis – cell drinking ► Receptor-Mediated Endocytosis

10. Check for understanding ► Compare and contrast active and passive transport

11. Cell signaling Epinephrine – increases heart rate, dilates blood vessels, dilates pupils, elevates blood sugar

12. Assign one to each group member ► Communication by direct contact  Cell junctions  Cell-cell recognition ► Local signaling  Paracrine  Synaptic signaling ► Long Distance  Hormones  Nervous system

13. What is the relevance of cell signaling ► Another example - Caffeine Caffeine

14. Three stages of cell signaling Three stages of cell signaling

15. Reception ► Reception on the plasma membrane (3 main types)  G protein coupled receptors  Receptor tyrosine kinase Receptor tyrosine kinase Receptor tyrosine kinase  Ion channel receptors Ion channel receptors Ion channel receptors ► Intracellular receptors Intracellular receptor

16. Reception in epinephrine G protein coupled receptors

17. Transduction ► Signal cascade – one molecule activates the next (usually by phosphorylating it)

18. Transduction in epinephrine

19. Response ► Response can be…  a gene being expressed (making a protein  Replication of the cell  Activation of an enzyme  Change in cell shape  Programmed cell death  And much more!

20. Response in epinephrine

21. Cancer can be caused by an error in signal molecules or transduction pathways