Fluid Mosaic Model

2. Fluid Mosaic Model • Current model of the membrane structure. • Phospholipid fluid sea in embedded with a wide variety of protein molecules.

3. Cell Membrane • The cell membrane is also known as: • Phospholipids bi-layer • Plasma membrane • Fluid mosaic membrane

4. What is a Solution? • Is a homogeneous mixture • A combination of a Solute and Solvent. • Large part is the solvent • Small part is the solute

5. What is a [ ] Gradient? • Is when there is an uneven distribution of a substance across a solution. • High to low concentration [ ] • Low to high concentration [ ]

6. Understanding solutions • More Solvent • Less Solute • Less solvent • More Solute solute solvent

7. Understanding solutions Hypotonic solution Hypertonic Solution solute solvent

8. Understanding solutions • Hypotonic Solution • Hypertonic solution Cell solute solvent

9. Understanding solutions • The solution has solvent and solute • The cell has solvent and solute too. solute

10. Who has more solute? What type of solution is this cell in?

11. What will happen to this cell? H2O Cell Shrinks

12. Who has more solute? What type of solution is this cell in?

13. Lysis H2O Cell Swells

19. Hypertonic Solution Plant Cells Animal Cells

21. Hydrophobic vs Hydrophilic • Hydrophilic (attracted to water) • Hydrophobic (not attracted to water but are attracted to other hydrophobic tails) • They have a hydrophilic phosphate head and two hydrophobic hydrocarbon tails. • Cell membranes are made up of a double layer of these phospholipid molecules. • The phospholipidbilayer makes the membrane very stable but also allows flexibility. • The phospholipid in the membrane are in a fluid state which allows the cell to change it’s shape easily.

22. Osmotic Pressure • The pressure of water moving across a membranes cause by a concentration gradient.

23. Turgor Pressure • Is a hydrostatic pressure due to a plant cell being placed in a hypotonicsolution. • Is pressure on inside of a cell against the cell wall. • Only in plant cells

24. What is Plasmolysis? • The Shrinking of cell membrane from cell wall in a plant or bacterial cell, caused by loss of water through osmosis. • from Greek lusis, a loosening.

25. What is Crenation? • Crenation is the contraction of a cell after exposure to a hypertonic solution, due to the loss of water through osmosis. • Crenation occurs because in a hypertonic environment, osmosis . • As a result the cell shrinks and forms abnormal notchings around its edges.

26. What is cytolysis? • Cytolysis, or osmotic lysis, occurs when a cell bursts due to an osmotic imbalance that has caused excess water to move into the cell. • It occurs in a hypotonic environment. • Where water moves into the cell by osmosis where the volume exceeds the membrane's capacity and the cell bursts. • The presence of a cell wall prevents the membrane from bursting, so cytolysis only occurs in animal and protozoa cells which do not have cell walls.

27. Active or Passive Transport • Endocytosis • Diffusion • Exocytosis • Osmosis • Oxygen • Carbon dioxide • Sugar • Water • Pinocytosis • Phagocytosis

38. Leaf Anatomy