1.  Main component is the PHOSPHOLIPID Fatty acids Hydrophilic head -polar Hydrophobic tail -nonpolar Phosphate group

3. Simplified Cell Membrane

6. Cell-cell recognition Glycoproteins may serve as ID tags that are recognized by other cells

7. Attachment to the cytoskeleton and the extracellular matrix Protein and carbo mix located outside the cells

8. Enzymatic Activity Examples:  disaccharides in small intestine  many enzymes involved in photosynthesis and cellular respiration

9. Signal Transduction Protein may have binding site for a hormone which relays a message to the inside of the cell.

10. Intercellular joining Examples in animal cells -tight junctions -gap junctions -anchoring junctions

11. Tight Junctions Proteins hold cells together and don’t allow passage of material between cell. Important in epithelial cells lining intestine. Nutrients inside intestine must pass THROUGH cells. Not between.

12. Tight junctions Anchoring junction -keeps cells from being pulled apart Gap junctions Plasma membranes of adjacent cells Extracellular matrix

13. Gap Junctions  -molecules can pass directly from cytoplasm of one cell to the next.  Found in cardiac muscle and some neurons.  Speeds communication between cells

14. Found in plant cells Connection between plasma membrane and cell wall. Allow molecules to move from one plant cell to another

16. This means it allows some things to pass but keeps some things out What can pass and what cannot? Where do things pass through? Some through lipids Some need the proteins The Plasma Membrane is

17. Lipid portion of the plasma membrane Small nonpolar molecules can pass through O 2, CO 2 Charged ions or polar molecules cannot pass through Lipids can pass -ex: steroids Na+ How can they get in or out??????

19. Diffusion Depends on concentration gradients low Goes from high concentration to low concentration Diffusion stops when there is no more concentration gradient Individual molecules still are moving however The system is then said to be in equilibrium Passive Transpor t

21. Facilitated Diffusion STILL DIFFUSION Direction of movement of molecules???? Needs help (facilitation) of a protein.

22.  DIFFUSION OF WATER ACROSS A SELECTIVELY PERMEABLE MEMBRANE  STILL DIFFUSION  PASSIVE  NO ENERGY REQUIRED Uses channel proteins called aquaporins

23. The direction that WATER goes during osmosis depends on the amount of dissolved solutes on either side of the membrane If there are more solutes, there is less available water

24. they refer to the concentration of solutes in that solution Isotonic Hypertonic Hypotonic terms used to compare solutions.

28. ACTIVE TRANSPORT Moves molecules AGAINST their concentration gradient -”uphill” -requires a membrane protein -source of energy -usually ATP

29. Large molecules may cross the membrane by exocytosis and endocytosis Exocytosis -substances move out of the cell by packaging them in vesicles which fuse with the plasma membrane

30. Movement of large materials across the membrane Phagocytosis (cell eating) -large particles Pinocytosis (cell drinking) -dissolved solutes Endocytosis  bringing into the cell by way of vesicle (vacuole) formation

32. Pincytosis is indiscriminate. Cells use receptor- mediated endocytosis to take up specific substance

33. 4.6% solution 5.2% solution

34.  An outer membrane (the plasma membrane)  Genetic material (DNA)  Something to build proteins (ribosomes)

35.  Cells can be categorized into one of the following two groups  PROKARYOTIC  EUKARYOTIC

36.  Literally means “NO nucleus”  Earliest fossils are prokaryotes  Have DNA (but not organized into a nucleus)  Have ribosomes (to build proteins)  Are “simple” cells  Have no membrane bound organelles  Include the bacteria and archaea

38. A B C D

39.  Contain a nucleus and membrane bound organelles  Includes us, plants, fungi, protists