Diffusion & Osmosis (Active and Passive transport and how materials move in the cell)

Homeostasis All living things have certain requirements they must satisfy in order to remain alive – Keep a balance: Balance of temp, water, salt, nutrition TO DO THIS, THINGS MUST BE ABLE TO MOVE IN A CELL

Selectively Permeable Porous- like a screen on a window Lipid bilayer… A membrane that allows only certain materials to cross it Materials pass through pores in the membrane

Active transport requires energy. (molecules move from an area of lesser to higher concentration) BrainPop Active Transport

PASSIVE TRANSPORT needs NO ENERGY! (molecules move from an area of higher to lesser concentration). BrainPop Passive Transport

Diffusion The movement of molecules from high concentrated to less concentrated. BrainPop Diffusion

Diffusion

Osmosis The diffusion of water across a selectively permeable membrane. Osmosis is a type of Passive Transport. Osmosis requires NO ENERGY.

TYPES OF SOLUTIONS Hypertonic- a solution that causes a cell to shrink because of Osmosis. Hypotonic- a solution that causes a cell to swell because of Osmosis. Isotonic- a solution that causes no change in the size of the cell

Osmosis In this picture a red blood cell is put in a glass of distilled water. Because there is a higher concentration of water outside the cell, water enters the cell by OSMOSIS. In this case too much water enters and the cell swells to the point of bursting open.

3ETKAZYC Hypotonic and hyper tonic solution video clip

Summary Diffusion is: _______________ Osmosis is the: _______________ Active transport requires________. (molecules move from an area of _______ to ____________ concentration) Passive transport needs __________! (molecules move from an area of ________ ___ _______________concentration).

Summary Diffusion is the movement of molecules from an area of higher concentration to an area of lesser concentration. Osmosis is the movement of water thru a semi permeable membrane. Active transport requires energy. (molecules move from an area of lesser to higher concentration) Passive transport needs NO ENERGY! (molecules move from an area of higher to lesser concentration).

Why are osmosis & diffusion important? All living things have certain requirements they must satisfy in order to remain alive – maintain homeostasis These include exchanging gases (usually CO2 and O2), taking in water, minerals, and food, and eliminating wastes. These tasks happen at the cellular level. Molecules move through the cell membrane by diffusion A balance, or EQUILIBRIUM, must be maintained.