CELLS – Chapters 6, 7, 11, 12

1. CELLS – Chapters 6, 7, 11, 12 Cell Structure, Membrane Function, Cell Communication and the Cell Cycle/Mitosis

2. CELLS are based on Cell Theory states that 1. all living things are made of cells 2. all cells come from other cells 3. Cells are the most basic unit of life Cell structures & function Cell replication Ch 6, 7, 11 Ch 12

4. Endomembrane System • Secreted or membrane-bound proteins only • (Free ribosomes synthesis soluble cytosolic proteins)

5. Cells are dynamic! • Cell division & growth • Metabolism • Building proteins and other cell parts (anabolism) • Catabolism • Repair of damaged cell parts • Chemical reactions to stay alive and maintain homeostasis • Cell communication

6. Membrane Structure & Function

7. Critical components of selectively permeable membrane • Phospholipids – barrier • Cholesterol – regulates fluidity • Transmembrane proteins – render selectivity • Receptors • Ion channels • Aquaporins – allow water to pass into/out of cell • Transport proteins • Outer leaflet • Carbohydrates – cell identification • Extracellular matrix (ECM) – interaction with surroundings

8. Types of molecular movement across the cell membrane • Passive Transport • Diffusion • Facilitated Diffusion • Osmosis • Active Transport • Bulk transport: Endocytosis/Exocytosis/Pinocytosis

9. Terms to know: • Concentration gradient – a form of stored energy • Solute • Solvent • Isotonic • Hypertonic • Hypotonic • Equilibrium

11. Phrases to know • Passive transport • Molecules move down/with their concentration gradient • From high concentration to low concentration • Active transport • Molecules move against their concentration gradient • From low concentration to high concentration • Requires input of ATP energy from cell

12. Passive transport - Diffusion In the absence of any partitions, molecules will move from an area of high concentration to an area of low concentration

13. Molecules of dye Membrane Equilibrium (a) Passive transport of one type of molecule Equilibrium (b) Passive transport of two types of molecules Diffusion across a cell membrane • What types of molecules can cross the membrane barrier freely? http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html

14. Passive transport - Facilitated Diffusion • Requires a protein channel • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_facilitated_diffusion_works.html

15. Passive transport - Osmosis • Movement of H2O through aquaporin proteins • Depends on water potential – the direction water molecules will flow is determined by solute concentration on either side of the membrane • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

16. Remember secondary and tertiary structure???

18. The effects of osmosis differ in plant and animal cells Animal cell Lysing Normal Shriveled Plasma membrane Plant cell Plasmolysis Flaccid(wilts) Turgid(normal) (a) Isotonic solution (b) Hypotonic solution (c) Hypertonic solution

19. Active Transport • Moves solutes against their concentration gradient via a transport protein • http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.html

20. Active transport – bulk transport via exocytosis, endocytosis & pinocytosis http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__phagocytosis.html

21. Receptor-mediated endocytosis

22. Receptor-mediated endocytosis: cholesterol uptake http://bcs.whfreeman.com/thelifewire/content/chp05/0502003.html

23. Visual Summary 5.2

24. Cell Signaling • Cells communicate with one another for several reasons • Growth • Development • Stimulate immune response • Regulate gene expression • Relay/transmit signals in nervous system • Fight or flight response • Homeostasis (example: regulate blood glucose)

26. Three stages of cell signaling • Reception, Transduction, Response • Animations: Ch 11 http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__receptors_linked_to_a_channel_protein.html

29. Ch 12 – Mitosis & the Cell Cycle

30. Mitosis: duplicating cells • Occurs in somatic cells (body cells) throughout life • Wound healing • Growth • Repair/maintenance (skin, intestine, hair follicles, replacement of uterine lining after menstruation)

32. Results of (normal) Mitosis • 2 genetically identical cells (“daughter cells”) http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__mitosis_and_cytokinesis.html

33. Checkpoints regulate the cell cycle

34. Interplay of Cyclin and Cdk proteins regulates progression through the cell cycle

35. Normal cell division has 2 key characteristics: • Density-dependent inhibition • Anchorage dependency • Cells that are not adhered to a surface will not proliferate • Cells use cell signaling to detect growth factors and density signals