Mr. Drake

 Membrane is “_____________________”: only allows certain things to enter the cell  The lipids prevent too much water from entering or exiting the cell  Small, uncharged, molecules pass through easily (O 2, CO 2 ).

 Concentration of molecules is equal inside the cell and outside of the cell  This is how we achieve homeostasis  The cell is always moving towards equilibrium Concentration – amount of molecules in a given space Example: 5 grams/liter

 Transport that does NOT require energy 1) 2) 3)

 Simplest type of transport  Movement of molecules from an area of _______________________(MORE)to an area of ______________________(LESS)  ______________________: difference in concentration of molecules across a space  Molecules move down their concentration gradient  Molecules will do this without energy

 Cell membranes are selectively permeable  Go from high concentration to low concentration  Depends on the size of the molecule, smaller is better  Calcium, sodium and water pass easily

 Movement of _________ across the cell membrane  Again, it goes from high to low concentration  Does not require energy it is passive

 _____________: having a lower solute concentration, and therefore a higher water concentration, relative to another solution.  Example: If the cell is sitting in a hypotonic solution, then water will flow into the cell.  _____________: Having a greater solute concentration, and therefore a lower water concentration, relative to another solution.  If the cell is sitting in a hypertonic solution, then water will flow out of the cell.

Direction of osmosis HypotonicWater into the cell HypertonicWater out of the cell Isotonic = Into and out of the cell at equal rates Solution outside of cell Direction of Osmosis _____________-having an equal solute concentration and water concentration relative to another solution. If a cell is sitting in an isotonic solution, water will flow into and out of the cell at equal rates.

 Most get to equilibrium easily as water passes across membranes  Cells live in a ______________ environment, water all around them  If too much water enters the cell it will burst  Cells must manage water and solute levels to prevent dehydration

 For molecules that can’t pass through the membrane  Either too large or not lipid-soluble  Proteins in the membrane help push them through  From high to low concentration  The proteins will change their shape and this pushes the molecules through

 Ion channels in the cell membrane act like gates in a fence  Allow sodium, calcium, potassium, and chloride to flow into cell (Ca+, K+, Cl-)  Useful in nerve and muscle cells

 1) Sodium-Potassium Pump  2) Endocytosis  3) Exocytosis

 From _________________concentration— AGAINST concentration gradient  Uses energy-Active  1) ______________________: in muscle cells uses energy  Creates electrical impulses like in nerve cells

 Push proteins and hormones “up” the concentration gradient  Key to survival of animal cells  Sodium potassium pump: Animals must have more sodium outside and potassium inside to allow for energy production in cells  Can move small and large molecules using this method

 2) ________________: large molecules like food into the cell  3)________________: Large molecules out of the cell

 Opposite of endocytosis, cell releases large amounts of material through the membrane  Removes waste from the cell  Important to maintaining homeostasis in cells

 Cells of animals live in a salty or “saline” solution  This allows them to survive in a variety of different environments  Cells must maintain fluid levels or they die  Most animals will have a kidney type organism to manage these levels in the body

 Filter the blood of animals through osmosis and diffusion  Prevent dehydration and maintain fluid levels  Prevent toxins from building up in the blood  Eliminate swelling in the body

 When Kidneys fail harmful toxins build up in the blood  CKD (chronic kidney disease), cancer, aging and drug/alcohol abuse lead to kidney failure  Tubing that removes toxins, Takes 3-4 hours 3 times a week