Bellwork How to materials get into and out of the cell?

Ch. 4- Membrane Structure & Function Ch Permeability of the Plasma Membrane

Target #21- I can describe the passage of molecules through the plasma membrane  The plasma membrane regulates the passage of molecules into and out of the cell  Membrane is differentially(selectively) permeable  certain substances can move across the membrane while others cannot  Water and small, uncharged particles, can freely cross the membrane  Able to slip between the phospholipids  Go down the concentration gradient  move from areas of high concentration to areas of low concentration  Large molecules and ions are unable to freely pass through the membrane  Cross through channel proteins, carrier proteins, or vessicles

f  Diffusion: the movement of molecules from a higher concentration to a lower concentration until equilibrium  Down the concentration gradient  Occurs with only a few types of molecules  A solution contains a solute, a solid, and a solvent, a liquid  Ex: when we breathe in oxygen, the concentration is higher in the lungs, and then moves to the area of lower concentration, the blood Target #22- I can state the direction molecules travel through diffusion

Target #23- I can list the factors that affect diffusion  Several factors influence the rate of diffusion  Temperature  Pressure  Electrical currents  Molecular size

Checking for Understanding What is diffusion? What are the factors that affect the rate of diffusion?

Target #24- I can define osmosis Target #25I can identify a cell is in an isotonic solution when given a scenario or picture  Osmosis: the diffusion of water across a differentially permeable membrane due to concentration differences  Isotonic solutions: the solute concentration and the water concentration both inside and outside the cell are equal  No net loss or gain of water

Checking for Understanding How is osmosis different from diffusion?

f  Hypotonic Solution  Solutions that cause cells to swell due to an intake of water  Concentration of solute is less on the outside of the cell then on the inside of the cell  Water enters the cell  Net movement of water is into the cell  Cytolysis: used to refer to ruptured cells  Turgor pressure: the swelling of a plant cell in a hypotonic solution Target #26- I can identify a cell is in a hypotonic solution when given a scenario or picture

Target #27- I can I can identify a cell is in a hypertonic solution when given a scenario or picture  Hypertonic Solution  Solutions that cause cells to shrink due to a loss of water  Higher percentage of solution in solution than the cell  Net movement of water is out of the cell  Crenation: refers to the shriveling of a cell in a hypertonic solution  Plasmolysis: shrinking of the cytoplasm in a plant cell due to osmosis

Checking for understanding- What is happening in each picture?