1. Cell Transport

3.  The molecules can move freely in the membrane.  They are constantly renewed during a cell's life span.  Grow with the growth of cell and its organelles.  Regenerate to some extent in cases of minor disruptions.  Contract and expand during cell movements.  Allow interactions of cells such as recognition of self and fusion of cell.  Regulate the flow of materials passing through them. These properties indicate that biomembranes are fluid and dynamic.

4.  Fluid - highly viscous fluid  Mosaic = matrix of…  Bilayer of phospholipids  Globular proteins embedded ▪ Channel proteins (doorways) ▪ Marker proteins (name badge) ▪ Receptor proteins (on/off switch)

6.  The membrane is only as good as its parts  Phospho- portion is polar and attracts  -lipid portion is nonpolar and repels  Jobs:  Acts as a barrier  Transports materials  Transfers materials  Processes materials

8. Why does too much fertilizer burn your lawn? Inside the cell membrane

9.  The amount of a substance per volume is the concentration  The concentration of molecules ranges from high to low, hence gradient.  But molecules  are in constant motion  collide into & bounce off of one another  eventually spread out evenly = equilibrium

11.  maintain a constant internal conditions (homeostasis)  respond to their environment (the concentration gradient)  balance between inside and outside concentrations occurs to create equilibrium  molecules are transported into the cell if there’s more outside the cell  molecules are transported out of the cell if there’s more inside the cell

12.  Passive Transport  Simple diffusion (solute)  Facilitated diffusion (with help)  Osmosis (water)  Molecules move with the concentration gradient (from high to low)  Requires no energy

14. Carrier or channel proteins help large molecules to diffuse from high to low

15.  Water movement from high to low concentrations  Osmotic pressure is the force exerted on the cell membrane from the water found on either side of the cell membrane  Osmotic (water) pressure gives plant cells turgidity (crisp veggies vs. soggy)

16. When is equilibrium reached in a solution?  When equal concentrations of molecules are found throughout the solution or on either side of a semi- permeable membrane, like that of a cell.

17.  Active transport – move against gradient (from low to high )  Sodium-potassium pump  Endocytosis (cell eating – think PacMan) to form vacuoles  Exocytosis (cell pooping) to rid cells of waste

21.  The [concentration] of dissolved solutes inside/outside of the cell.  Start by determining the concentration of solutes found inside the cell.  Then determine the concentration of solutes found outside the cell.  Compare the two.

22.  concentration of dissolved solutes is equal to cell contents  Cell is in equilibrium with its environment  No net movement of solutes or water in either direction  Molecules are still moving but equally in BOTH directions

23.  Concentration of dissolved solutes is greater than cell contents  Water moves out  Cell size shrinks = “skinny” cell

25.  concentration of dissolved solutes is less than cell contents  Water moves in and solute moves out  Cell size swell/increase = “hippo-fat” cell