Vocab Solute – stuff we want to dissolve Solvent – substance in which something dissolves Concentration – amount of a solute dissolved in a given volume of solution A lot = concentrated A little = dilute

Passive transport No energy needed Particles move from high concentration to low concentration Particles flow until equilibrium is reached No change in concentration on each side Diffusion = particles moving across membrane Osmosis = water moving across membrane

Diffusion and Membrane Membrane has selective permeability Polar/nonpolar regions on lipid bilayer Cannot pass through: Ions (salts dissolved in water) Hydrophilic molecules (glucose) Macromolecules

Facilitated Diffusion Proteins in membrane move particles across

Facilitated Diffusion Carrier proteins Change shape

Osmosis Diffusion of water across membrane

Osmosis Isotonic – concentration of solute is the same inside and outside cell Water enters and leaves at same rate

Osmosis Hypotonic – concentration of solute is greater inside the cell, more water outside cell Cells gain water Animal cells can burst Cell wall prevents plant cells from rupturing Turgor pressure supports the cell A cell under pressure is turgid

Osmosis Hypertonic – concentration of solute is greater outside the cell Cells lose water Animal cells shrivel up Plants: membranes pulls away from the cell wall The cell wall is rigid and does not shrink

Active Transport Substances moving from low to high concentrations Need energy Use proteins in membrane

Na/K ATPase Pump Found in animal cells Helps maintain levels of sodium and potassium Uses energy (ATP) to move 3 Na ions out of the cell and 2 K into the cell High levels of sodium on outside creates a gradient

Coupled Transport Linked, simultaneous transport of two substances across a cell membrane Create a high concentration gradient on 1 side Protein channels open & allow other particles (sucrose/sugar) to move across membrane Spend very little energy

Transport of Large Particles Endocytosis –brings substance into cell

Transport of Large Particles Exocytosis – expels stuff from cell waste, substances (hormones) produced by cell

In passive transport, particles move from what to what concentration? Agenda for Tuesday Nov 22nd Finish notes Finish lab Osmosis worksheet

What is wrong with the cartoon? Agenda for Friday Nov 20th Go over cell worksheets Finish gummy bear lab Finish notes Osmosis practice sheet Test Tuesday