1. Cell Communication II Chapter 15

2. An animal cell depends on extracellular signals to survive or divide

3. An animal cell depends on extracellular signals to differentiate. Without extracellular signals the cell will die

4. Signaling molecules must be turned over rapidly; if turnover time is one minute concentration can decrease rapidly

5. Extracellular signaling molecules can bind to intracellular receptors

6. Acetyl choline causes release of NO which results in rapid relaxation of smooth muscle cells

7. Signaling molecules that bind to nuclear receptors are small and hydrophobic

8. Inhibitory proteins make receptor inactive when not bound to the signaling molecule

9. When signaling molecule binds receptor binds DNA and increases gene transcription

10. Nuclear receptors have a DNA binding domain

11. Extracellular signaling molecules can bind to cell surface receptors

12. 3 large classes of cell surface receptors; ion channel linked receptors

13. Active Chemical Synapse

14. 3 large classes of cell surface receptors; G protein linked receptors

15. 3 large classes of cell surface receptors; enzyme linked receptors

16. G-protein linked receptor

17. The structure of an inactive G-protein

18. Without signaling molecule G-protein is inactive

19. G-protein binds to receptor when signaling molecule is present

20. G-protein accepts GTP and disassemble into two active subunits

21. The α subunit of the G-protein can be deactivated through hydrolysis of GTP

22. Deactivation of G-protein

23. Reassembly of α subunit with other 2 subunits reforms inactive G-protein complex

24. Arrestin binds phosphorylated G-protein receptor and deactivates the receptor and prepares it for endocytosis

25. DVD clip 61

26. Release of cAMP inside cell caused by serentonin and mediated by a G-protein

27. Synthesis and degradation of cyclic AMP

29. Activation of cAMP dependent protein kinase

30. Activation of gene transcription by cAMP