Cells…

Homeostasis Maintaining a cells internal environment. CELL MEMBRANE When you sweat

Means it can move! Fluid Mosaic Model

Phospholipids Fatty acid Phosphate Tails—scared of H 2 O –Hydrophobic Heads—Love H 2 O –Hydrophilic Makes a bilayer

Cell Membrane Separates Made of phospholipids and other macromolecules (protein and carbs) Selectively permeable –Only allows certain things in and out

Diffusion and Osmosis

WATER, WATER EVERYWHERE Water is the 2 nd most important thing in the body….the only thing that beats it is oxygen. SO…… You can live for weeks without food, but only about 3 days without water. YOUR BODY NEEDS WATER TO CARRY ON ITS PROCESSES…And in order for the water to move through the cells of our body two processes take place. Osmosis and Diffusion

OSMOSIS the movement of WATER from an area of high water concentration to an area of low water concentration.

The MORE water the LESS molecules RIGHT???? SO…… In this picture water is moving left to right, from an area where there is high amounts of water to an area where there is low amounts of water. HIGH TO LOW!!

DIFFUSION MOLECULES spread from areas of high molecule concentration to areas of low molecule concentration.

Let’s Review Water….. Osmosis……The movement of WATER from an area of high water concentration to an area of low water concentration Diffusion……The movement of MOLECULES from an area of high molecule concentration to an area of low molecule concentration.

Transporting “Stuff” In and Out of the Cell Passive Transport: DIFFUSION- If the molecules are small enough. What happens though if things need to pass, but can’t get through???

Facilitated Diffusion If molecules are too big to pass through the membrane, but still are going HIGH to LOW! They need a facilitator—a helper!

Active Transport: If substances are going LOW to HIGH! They use ATP!! Where does ATP come from?

Active Transport

ENZYMES as CATALYSTS "Catalyst" a substance that increases the rate of a chemical reaction, and is never changed or used up by the chemical reaction.

THIS HAPPENS MUCH FASTER, BECAUSE OF THE ENZYME.

WHAT IS AN ENZYME? A PROTEIN that makes a chemical reaction go faster! Affected by temperature and pH. temps- speed up enzymes temps- slow enzymes down

Lock and Key Induced Fit- Making them fit together

Macromolecules Proteins— Most important macromolecule. Makes up most of our cells. Made up of amino acids. aa – aa – aa – aa = protein Carb—Major energy source of cell

Macromolecules Lipids— FATS– build up the cell membrane (phospholipid bilayer). Nucleic Acids– DNA and RNA—heredity.