7-3 Cell Membrane The cell membrane regulates what enters and leaves the cell It is made of a double layer sheet called a lipid bilayer

Proteins move material across the cell membrane Carbohydrates act like chemical identification cards Outside of cell Inside (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains

Cell Walls They are found in plants, algae, fungi and prokaryotes They are OUTSIDE of the cell membrane It provides support and protection for the cell They are made of cellulose

Diffusion The cytoplasm is a “solution” of many substances in water Concentration=mass/volume Diffusion is the process by which molecules move from an area of high concentration to an area of low concentration

Glucose molecules High Concentration Cell Membrane Low Concentration Protein channel

Osmosis Selectively permeable means that only some substances can pass through Osmosis is the diffusion of water through a selectively permeable membrane

Water diffuses from an area of high concentration to an area of low concentration Diffusion will stop once equilibrium is reached

In comparing the inside of the cell to the solutions on the outside of the cell: Isotonic- the solution on the outside has the same concentration as the solution inside the cell Hypertonic- the solution outside has a HIGHER concentration of solutes than the solution inside the cell. Hypotonic- the solution outside has a LOWER concentration of solutes than the solution inside the cell. Pressure is exerted on the hypertonic side

Facilitated Transport Also known as Facilitated Diffusion Molecules that cannot pass through the lipid bilayer move through protein channels instead Protein channels allow large molecules to pass

Active Transport The energy-requiring process that moves material across a cell membrane against a concentration difference Active transport does not always require transport proteins

Endocytosis- process of taking materials into the cell by means of infoldings of the cell membrane (forming a vacuole in the cytoplasm) Phagocytosis- process of taking large particles into the cell Exocytosis- the release of large amounts of material from the cell