1. Cellular Transport and the Cell Cycle

2. Types of Transport  Passive Transport-requires no energy for something to move with a concentration gradient (from high to low concentration).  Active Transport-requires energy for something to move against a concentration gradient (from low to high concentration).

3. What is osmosis?  Osmosis is the ________________________________.  Osmosis is passive transport-it requires no energy.  Water will move to balance out the concentration gradient.  A concentration gradient is the comparison of concentration on two sides of a permeable membrane. Osmosis-McGraw Hill

5. Types of solutions:  A solution is when something is dissolved in a liquid, usually water.  Remember these terms?  Solute-What is dissolved  Solvent-The liquid (usually water) that something is dissolved in.  There are three types we see in cells:  Isotonic Solutions  Hypotonic Solutions  Hypertonic Solutions

6. Isotonic Solutions:  In an isotonic solution the concentration of dissolved substances in the outside solution is the same as the concentration of dissolved substances in the cell.  The concentration of water is the same inside and outside of the cell.  Osmosis does not occur because water is moving into and out of the cell at the same rate.

8. Hypotonic Solutions  In a hypotonic solution the concentration of dissolved substances in the outside solution is lower than the concentration of dissolved substances in the cell.  The concentration of water is greater outside of the cell.  Osmosis occurs because water is moving into the cell which causes the cell to swell.

10.  Animal cells may lyse or rupture if the concentration difference is too large.  This is what happens if you drink too much water. This can kill you and is called water intoxication, water poisoning, or hyponatremia.  Plant cells have a cell wall so they cannot lyse. They will swell to fill the available space and the plant cell becomes more firm. This is called turgor.  This is why the grocery store mists the produce…so that they look bigger and firmer.

12. Hypertonic Cells  In a hypertonic solution the concentration of dissolved substances in the outside solution is higher than the concentration of dissolved substances in the cell.  The concentration of water is greater inside of the cell.  Osmosis occurs because water is moving out of the cell which causes the cell to shrivel.

14.  Animal cells may shrivel if the concentration difference is too large.  This is why you shouldn’t drink ocean water.  In plant cells when they lose water it mainly comes from the central vacuole. This causes the cell membrane and cytoplasm to pull away from the cell wall.  This is why plants wilt if they don’t have enough water.

18. Other Forms of Passive Transport  Facilitated Diffusion is when materials move across a membrane using proteins.  Channel proteins pass all the way through a cell membrane. This is like a tunnel through a mountain.  Carrier proteins change shape to allow a substance to pass through a cell membrane. This is like a turnstile to get on the subway.  Do these require energy? ______ Facilitated Diffusion from McGraw Hill

20. Active Transport  Active Transport moves against a concentration gradient and requires energy.  It can happen with carrier proteins.  The movement of large molecules can be in the form of:  Exocytosis  Endocytosis  Pinocytosis  Phagocytosis

21.  Carrier Proteins are usually specific for a substance. When the proper molecule enters, it changes shape to move the molecule to the other side.  It works like a pump.  This is required to maintain homeostasis.  One example is the sodium-potassium pump. Sodium-Potassium Pump

22.  Exocytosis is how the cell gets rid of large substances (often waste).  This is also how cells secrete hormones.

24.  Endocytosis is when the cell takes in large molecules or even whole cells. There are two types:  Pinocytosis-Cellular drinking of liquids.  Phagocytosis-Cellular eating of solids. Endocytosis and Exocytosis