1. Cell Membranes & Walls

2. Types of Cells Prokaryotes Archaebacteria Eubacteria * Eukaryotes Plants * Animals * Fungi Protists

3. Why do cells have a membranes/walls?

4. Functions of Cell Membrane 4 Separates & protects cell from its surrounding environment Protein molecules inside the cell membrane act as channels & pumps that move different molecules into & out of the cell. Receptor proteins in cell membrane allow cells to detect external signaling molecules such as hormones

5. Evolution of Cell Membrane 4 Current Theory: 1st prokaryotic cell membrane was a single layer of lipids

6. Phospholipid Hydrophilic Head (Polar) : Polar Group + Phosphate + Glyerol Hydrophobic Tail (Non Polar) : 2 Fatty Acid Chains

7. To Try... 1.Use a disposable pipet to place a drop of water on the 2 different kinds of spoons 2.Sketch & Describe what you see

8. Phospholipid Bilayer When phospholipids are placed in water they usually form a sphere.

9. To Try... 1.Fill a petri dish halfway with water 2.Use a disposable pipet to drop oil onto the water 3.Sketch and describe your observations

10. Modern Bacteria Cell Membrane Phospoholipid Bilayer

11. Cell Membrane Proteins Protein functions: Transport nutrients, waste, gases, etc. Chemical Receptors for the cell

12. Cell Membrane Characteristics Semi-permeable: the membrane allows the movement of some, but not all particles

13. Cell Membrane Characteristics Fluid Mosaic Model: it is a lot of small components that together make the cell membrane http://home.earthlink.net/~shalpine/anim/Life/memb.htm

14. Bacteria Cells 7 Gram Positive & Gram Negative Cell Wall & Membrane

15. Bacteria Cells Gram Positive: Phospholipid Bilayer + Thick Cell Wall (Peptidoglycan) Gram Negative: Phospholipid Bilayer + Thin Cell Wall + Phospholipid Bilayer

16. Gram-positive Cell Wall 8 & 9 Cell Wall: made of peptidoglycan (murein) = polymer of sugars & amino acids Cell Membrane: Phospholipid Bilayer is made of phoshates and lipid molecules

17. Gram-Negative Cell Wall What is different?

18. Gram Staining Protocol: 1) Apply a primary stain (crystal violet or methylene blue) to bacteria 2) Add Mordant (Gram's iodine) & let stand for 10-60 seconds, then pour off excess 3) Rapid decolorization w/ alcohol or acetone, rinse after 5 seconds (TIME CRUCIAL) 4) Counterstain w/ safranin or basic fuchsin for 40- 60 seconds, wash excess

19. Gram Staining

20. Gram Positive: Purple Gram Negative: Pink

21. Endosymbiotic Theory 5 Organelles orginated as seperate prokaryotic organisms which were taken inside the cell as endosymbionts Mitochondria developed from proteobacteria Chloroplasts evolved from cyanobacteria

22. Endosymbiotic Theory 6

23. Eukaryotic Cell Membrane 1

24. Eukaryotic Cell Membrane 2 What is similar between this cell membrane and the bacterial cell membrane?

25. Plant Cell Wall 10 Cell Wall thick & rigid prevents enlargement of the plant cell helps the plant absorb, transport, & secrete substances Cell Membrane

26. Plant Cell Wall Pectin: Hemicellulose: Cellulose Microfibril:

27. Sources 1. http://www.elsomresearch.com/images/nanosomin/membrane.gif 2. http://home.earthlink.net/~dayvdanls/membrane1.GIF 3. http://www.williamsclass.com/SeventhScienceWork/ImagesCells/CellMembrane.jpg 4. http://en.wikipedia.org/wiki/Cell_(biology) 5. http://en.wikipedia.org/wiki/Endosymbiotic_theory 6. https://eapbiofield.wikispaces.com/file/view/endosymbiosis.jpg 7. http://www.cehs.siu.edu/fix/medmicro/pix/walls.gif 8. http://www.palaeos.com/Kingdoms/Prokaryotes/Images/GramPosCellEnvelope.gif 9. http://www.mansfield.ohio-state.edu/~sabedon/007gpce.gif 10. http://www.mansfield.ohio-state.edu/~sabedon/007gpce.gif

28. Cell Membranes are like Bubbles... Challenge: 1.Get a paper clip through the bubble without popping the bubble 2.Get a pencil through the bubble without getting it wet

29. Soap Membrane How does the soap membrane compare to the cell membrane?

30. Soap in Action Captures the lipid