Passive and Active Transport Cellular Movement Passive and Active Transport

Passive Transport Does NOT require ENERGY to move particles into or out of a cell Movement of particles from HIGHER concentration to LOWER concentration DIFFUSION – movement of particles OSMOSIS – movement of water

DIFFUSION The process in which molecules move from areas of HIGH concentration to areas of LOW concentration

DIFFUSION Example: Smell of baking cookies from the oven moving through the house.

OSMOSIS The diffusion of water molecules through a membrane

OSMOSIS Movement of WATER from a HIGHER concentration to a LOWER concentration Example: Plant taking in water during a rainy day.

Let’s Practice…

Let’s Practice… The concentration of oxygen particles inside a cell is 45 percent and outside the cell is 30 percent. What will most likely happen?

Let’s Practice… The concentration of water molecules inside a cell is 80 percent and outside the cell is 25 percent. What will most likely happen?

Let’s Practice… The concentration of hydrogen particles inside a cell is 33 percent and outside the cell is 62 percent. What will most likely happen?

Equilibrium In all cases, cells want EQUILIBRIUM! Too much (or too little) of a good thing is BAD for the cell!

When do the molecules stop moving? EQUILIBRIUM = molecules are evenly distributed

Active Transport Requires ATP ENERGY to move particles into or out of cell Movement of particles from LOWER concentration to HIGHER concentration Endocytosis Exocytosis

ENDOCYTOSIS Cell membrane encloses a vesicle filled with particles and absorbs it, BRINGING IT INTO the cell

EXOCYTOSIS Cell membrane encloses a vesicle filled with particles and PUSHES IT OUT of the cell

Active Transport Example: A person trying to squeeze into an already crowded elevator! It takes ENERGY to do so!

What happens to cells when put in salt water? This is why you do not want to drink salt water when you are lost at sea!

Water moves out of the cell to try to reach equilibrium Water moves out of the cell to try to reach equilibrium. The cell dries out, shrinks, and dies!