Unit 3 Sec 7.3 Homeostasis and Transport

I. Cell Wall A. Structure  Composed of cellulose (__________) Cellulose is a polysaccharide composed of smaller units called _______________ (glucose) Glucose protects and supports cell

II. Cell Membrane Cell Membrane:  Controls what enter and leave cell through selective permeability Boundary of every cell

II. Cell Membrane A. Membrane Lipids Phospholipid bilayer:  Polar hydrophilic head  Nonpolar hydrophobic tail Steriods:  Cholesterol provides strength and stability in movement

Cell Membrane

II. Cell Membrane B. Membrane Proteins Integral proteins: embedded in lipid bilayer & extend from interior  exterior of CM

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 cell membrane without the use of energy

III. Passive Transport How molecules move:  1. random fashion bouncing off other things  2. constantly in motion From high to low concentrated area Continue until equilibrium

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

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 cell membrane b) vesicle fuses w/ the cell membrane & 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