Get ready to take notes!

Cellular Transport! The process by which molecules are moved from one side of the cell membrane to the other Two Types –Active –Passive

Diffusion Particles in a liquid or gas spread out… … from regions of high concentration… … to regions of low concentration… …until the particles are evenly spread out. Dissolving KMnO 4 crystal

The difference between the regions of high concentration and low concentration The steeper the concentration gradient, the faster diffusion takes place High concentration gradient Fast rate of diffusion Low concentration gradient Slow rate of diffusion Concentration Gradient

Passive Transport Doesn’t require energy Move molecules from high to low concentration – Like coasting down hill on a bike!

Diffusion occurs because the particles in gases and liquids are moving.

“Semi-Permeable” or “Selectively Permeable” Membranes A semi-permeable membrane will allow certain molecules to pass through it, but not others. Generally, small particles can pass through… Partially permeable membrane …but large particles cannot

Partially-permeable membrane More free water molecules on this side of membrane Water-solute particle is too large to pass through membrane Free water molecules diffuse in this direction

Video

Osmosis Osmosis is the diffusion of water molecules… from a region of high concentration to a region of low concentration of water molecules…across a semi-permeable membrane…until they are evenly spread out.

VideoVideo 1 Video 2 Video

Passive Transport Does osmosis or diffusion require energy? No, molecules move along a concentration gradient (high to low).

Why are osmosis & diffusion important? All living things have requirements they must satisfy in order to remain alive – homeostasis Including exchanging gases (usually CO2 and O2), taking in water, minerals, and food, and eliminating wastes. These tasks happen at the cellular level.

Active Transport Requires Energy. ATP (form of energy made by mitochondria). Moves against the concentration gradient – LOW to HIGH

Active Transport Requires energy Moves molecules from low to high concentration –Like pedaling up hill on a bike

Endocytosis- Going “IN” to the cell Transporting material into a cell by the folding of a membrane.

Endocytosis- Going “IN” to the cell

Exocytosis- “EXITS” the cell Moves materials out of the cell

Video

Summary 1.What is Diffusion? 2.What is Osmosis? 3.What is Active Transport? 4.What is Passive Transport?

Let’s Sketch It- Active v. Passive Transport!

Let’s Sketch It- Endocytosis v. Exocytosis

HOMEOSTASIS CELLS AND THEIR ENVIRONMENT

LIFE’S BALANCING ACT If you are too hot or too cold your body temperature is out of balance

When we are too cold we shiver, it warms us up When we are too hot we sweat, it cools us down.

Your body is made up of cells. And, just like your body, cells must stay balanced. They must have just the right amount of materials to maintain the proper environment for your body.

HOMEOSTASIS The balance that all living things have to maintain, is called HOMEOSTASIS.