Unit 2 Sec 7.3 Homeostasis and Transport

I. Cell WallCell Wall  A. Structure  Composed of cellulose (__________)  Cellulose is a:  Glucose protects and supports cell

II. Cell Membrane  Cell Membrane:  Boundary of every cell

II. Cell Membrane A. Membrane Lipids  Phospholipid bilayer:  Steriods:  Cholesterol provides strength and stability in movement

Cell Membrane

II. Cell Membrane B. Membrane Proteins  Integral proteins: embedded in lipid bilayer & extend from:

C. Fluid Mosaic ModelFluid Mosaic Model  Phospholipid bilayer acts more like a fluid than a solid

III. Passive Transport  Passive Transport: the movement of substances across the CM:

III. Passive Transport  How molecules move:

III. Passive Transport  Factors Affecting the Movement  Temperature: hot= cold=  Size of pores and particle size  Mass

Types of Passive Transport  Diffusion  Osmosis  Facilitated Diffusion

A. DiffusionDiffusion  Diffusion: movement of molecules from an area of _______ concentration to an area of ________________ Diffusion  __________________________  Cool Science Trick Cool Science Trick  Concentration Gradient:

A. Diffusion  Equilibrium: concentration of substances in an area is _______  Results with:  Diffusion Across Membranes:

B. OsmosisOsmosis  Osmosis: diffusion of ________ molecules across cell memb. from area of _______ con. to an area of ________ con. Osmosis  Moves:

Who gets it? 1) What is diffusion? 2) What is equilibrium? 3) What is osmosis?

B. OsmosisOsmosis  Direction of Osmosis:  Hypotonic: Concentration of solute is lower outside the cell Hypotonic  Hypertonic: Concentration of solute is higher outside the cell Hypertonic  Isotonic: solutes in and outside the cell are equal Isotonic

Tonicity of a Cell SituationInside the cellOutside the cellDirection of H 2 O Draw it SoluteWaterSoluteWater In/Out? Hypotonic Hypertonic Isotonic

B. Osmosis  How Cells Deal w/ Osmosis:  Certain unicellular organisms must maintain a low level of water  Use_______________ to get rid of extra water  Contractile Vacuole:

B. Osmosis  How cells deal w/ Osmosis:  Plant root cells: need a __________ environment  Turgor Pressure:  Cytolysis  Hypertonic Environment.:  Plasmolysis:

C. Facilitated Diffusion  Facilitated Diffusion: substances require a ____________ for transport b/c it cannot diffuse through membrane Facilitated Diffusion  Molecules that use this transport:  Too big  Not charged  monomers

D. Diffusion through ion channels  Ion Channel: pathway for specific ion to pass through cell membrane Ion Channel  Stimuli will control gates to channels:  __________________

IV. Active Transport (AT) 1) AT: movement of materials from a area of ______ concentration to a _______ concentration using energy 2) Molecule is ___________ or not compatible with cell

IV. Active Transport 3) Bulk Transport:Bulk Transport Used to transport macromolecules or a large quantity of substance A) Endocytosis: a cell will engulf external substances into cell

IV. Active Transport A. Endocytosis (continued) -2 Types 1) Pinocytosis: cell ___________ 2) Phagocytosis: cell __________

Endocytosis and Exocytosis

IV. Active TransportActive Transport B) Exocytosis: process to remove materials from cell a) vesicle w/in the cell is sent to CM b) vesicle fuses w/ the CM& releases substance

IV. Active Transport  C. Pumps:  Proteins are embedded in the cell membrane  Molecules fit into the protein and are moved across from a _________ to _________ concentration