 A cell is a factory: an organism must obtain energy, raw materials, and eliminate waste.  These functions keep cells healthy so they can grow through cell division.  Cell growth allows cells to divide, therefore growing and repairing tissue as needed.

 Particles naturally travel from crowded areas (dense) to less dense places.  Diffusion is the process by which molecules spread from areas of high concentration, to areas of low concentration. When the particles are even throughout a space - it is called EQUILIBRIUM Diffusion

MOLECULES MOVE FROM AREAS OF HIGH CONCENTRATION TO AREAS OF LOW CONCENTRATION.

 Cells are surrounded by and filled with mostly water.  Diffusion of water is so important that it was given a special name – Osmosis.  Pure water has the highest concentration of water molecules.

 Pure Water would rush into a Red Blood Cell  Plasma – would maintain the Red Blood Cells  Salt solution would shrink the Cells

 Particles move through channels (protein cells). Diffusion and Osmosis are examples of Passive Transport - Thus no Energy is used for particles to move (High- Low) through a membrane.

 Active Transport usually involves the movement of small particles from an area of low concentration to an area of High concentration.  Thus using Energy to perform this process.

 Large Particles use Active Transpor t to move in and out of cells

 Reverse Osmosis is a process that forces water across semipermeable membranes under high pressure. The high pressure reverses the natural tendency of the solutes to travel from high to low concentration areas – this is how water is purified.

 Cell comes in contact with particle  Cell membrane begin to wrap around particle  The particle is completely surrounded – vesicles pinch off.  Endocytosis means “within the cell”

 Three Types: Phagocytosis, Receptor- Mediated and Pinocytosis.  Phagocytosis – captures large particles by sending out pseudopods (false feet)  Receptor Mediated – receptors on the membrane captures specific substances before endocytotic process begins.  Pinocytosis – the cell membrane usually surrounds a substance – forming a vesicle to carry it into the cell.

 Large particles are packaged in vesicles to leave the cell  Vesicle travels to membrane wall and fuses.  Cell releases the Vesicle  Exocytosis means “Outside the Cell”  Materials discharged from cell (vacuole passes plasma membrane to dump contents out of cell).

 Plants use the energy captured by chlorophyll to change carbon dioxide and water into food.  Glucose is a carbohydrate used by plants to convert sunlight into stored sugars (Energy).

 Cellular Respiration uses oxygen to breakdown food.

Photosynthesis: Uses Sunlight Energy and CO 2 to make Glucose and releasing O 2 Cellular Respiration: Cells use O 2 to breakdown glucose and Releases CO 2.