You should be able to: Define osmosis & diffusion. Determine why do we need to regulate osmosis. Identify what controls osmosis. Distinguish between a turgid cell, flaccid cell, and plasmolyzed cell. Define “Iso”, “hypo”, and “hyper”. Describe the water move during passive transport Know which type of passive transport requires a protein

Diffusion and Osmosis What is osmosis? – The diffusion of water across a selectively permeable membrane What is diffusion? - molecules moving from a high to low concentration…also called “going down the concentration gradient.” Why do we need to regulate osmosis? – To maintain homeostasis because the plasma membrane is NATURALLY permeable to water

Osmosis How long does water diffuse in a solution? - Until it is evenly distribution, or reaches equilibrium What controls osmosis? – The concentration gradient What is a concentration gradient? – The unequal distribution of particles

Osmosis in Plant & Bacterial Cells Plant cells have turgor pressure. Since they have a cell wall & central vacuole that stores extra water, there is water pressure inside a cell that pushes against the cell wall depending on how much water is inside the central vacuole.

Types of Solutions Remember: Salt Sucks Isotonic Solution: "ISO" means equal the concentration of solute is the same inside and outside the cell

Types of Solutions Hypotonic Solution: "HYPO" means less the concentration of solute is higher inside the cell than outside the cell

Types of Solution Hypertonic Solution "HYPER" means more The concentration of solute is higher outside the cell than inside the cell

Isotonic Solution SOLUTE: equal inside & outside the cell WATER: moves in both directions ANIMAL CELLS: stays the same PLANT CELLS: slightly firm WHICH CELL LIKES IT BEST: Animal

Hypotonic Solutions SOLUTE: more inside the cell WATER: enters the cell ANIMAL CELLS: swells PLANT CELLS: very firm WHICH CELL LIKES IT BEST: Plant

Hypertonic Solution SOLUTE: more outside the cell WATER: leaves the cell ANIMAL CELLS: shrinks PLANT CELLS: wilts WHICH CELL LIKES IT BEST: they both HATE it!!!!!!!

Passive Transport: molecules moving from a high to low concentration & this DOES NOT REQUIRE ENERGY..also called “going down the concentration gradient” Passive Transport –molecules moving from a high to low concentration & this DOES NOT REQUIRE ENERGY..also called “going down the concentration gradient” What type of diffusion needs the help of proteins for materials to move through the membrane? Facilitated diffusion

Types of Transport Proteins Channel Proteins- form channels that allow specific molecules to flow through. Carrier Proteins - change shape to allow a substance to pass through the plasma membrane.

Type of Transport What’s Happening Diffusion Molecules move from high to low concentrations Osmosis Water is diffusing (moving from high to low concentrations) Facilitated Diffusion Molecules move from high to low concentrations, but they need proteins to help them