2. Cell Theory 2006

3. Early Microscopes

4. 1600 England Robert Hooke  First to see cells Cork cells  Reminded him of monastery rooms

5. Holland 1600 Anton va Leeuwenhoek  Observed pond water Saw tiny organisms swimming

6. The Cell Theory All living things are made of cells Cells to be basic unit of structure and function in living things New cells are produced from existing cells  No spontaneous generation

7. Macromolecules & Cell Membrane Willems 2005

8. Standard: Cells are enclosed within semi- permeable membranes that regulate their interaction with their surroundings Most macromolecules in cells and organisms are made from a small collections of simple building blocks

9. Composite Cell Two Parts: nucleus cytoplasm

10. Membrane separates cell from the environment controls what enters and leaves  selectively permeable phospholipid bilayer with embedded proteins

12. Membrane Structure Double layer of phospholipids  hydrophilic heads to the outer edges  hydrophobic tails turned inward. lipid soluble molecules can pass I.E. gases & steroid hormones can pass

13. Membrane Structure Embedded cholesterol molecules help strengthen  Makes membrane impermeable to water-soluble substances.

15. Cell Membrane comprised of Carbon Compounds (Macromolecules)  Protein  Lipids Phospholipids  Carbohydrates

16. Movement across membrane Passive transport  does not use chemical energy diffusion facilitated transport

17. Diffusion passive movement of molecules from a higher to a lower concentration until equilibrium is reached.  Gases move through plasma membranes by diffusion.

18. Process of diffusion

21. Gas exchange in lungs occurs by diffusion

22. Osmosis diffusion of water across selectively permeable membrane Due to concentration differences  Always move from high to low concentrations  Water enters cells due to osmotic pressure within cells.

23. Osmosis demonstration

26. Osmosis in plant & animal cells solution  contains a solute (solid) and a solvent (liquid). Cells normally isotonic to their surroundings  solute concentration is the same inside and out of the cell.  Iso same as  tonocity strength of the solution

27. Osmosis in plant and animal cells

28. Hypotonic solutions  cause cells to swell and possibly burst. Hypo  less than. Animal cells undergo lysis in hypotonic solution. Increased turgor pressure occurs in plant cells in hypotonic solutions. Plant cells do not burst because they have a cell wall.

30. Osmosis in plant and animal cells Hypertonic solutions  cause cells to lose water. Hyper  more than  hypertonic solutions contain more solute. Animal cells undergo crenation (shrivel) in hypertonic solutions. Plant cells undergo plasmolysis, the shrinking of the cytoplasm.

32. Movement across membrane Active transport  requires chemical energy and usually a carrier protein.

33. Exocytosis (requires energy) transport macromolecules across plasma membranes  using vesicle formation.

34. Endocytosis ( which requires energy ) occurs as:  Phagocytosis large particles  Pinocytosis small particles  Receptor-mediated endocytosis specific particles

35. Phagocytosis (requires energy)

36. Pinocytosis (requires energy)

37. Receptor-mediated Endocytosis (requires energy)