Cell Membrane Outside of cell Inside of cell (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains

Membrane structure  Semi-Permeable  Selectively Permeable  Amphipathic~ hydrophobic & hydrophilic regions  Fluid Mosaic Model

Outside of cell Inside of cell (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains The Structure of the Cell Membrane

Membrane structure  Phospholipids~ membrane fluidity  Cholesterol~ membrane stabilization and fluidity  “Mosaic” Structure~  Integral proteins~ transmembrane proteins  Peripheral proteins~ surface of membrane proteins  Membrane carbohydrates ~ cell to cell recognition;

Video 1

Random movement results in  Solution – mixture of solute and solvent  Solute – substance being dissolved  Solvent – substance dissolving solute l Living Things (Universal Solvent)-Water

Membrane traffic  Passive transport~ diffusion of a substance across a biological membrane (NO ENERGY) [] = concentration  Diffusion~ the overall movement of particles from a region of high [] to an area of low [] l Osmosis~ the diffusion of water across a selectively permeable membrane

Results of Diffusion  Dynamic equilibrium l Once diffusion has evenly distributed the solute throughout the solvent; movement of particles continues with no change in []  Homeostasis l Preservation of equilibrium

Diffusion depends on [] gradient  [] gradient: the difference in [] of a substance across space  Diffusion is said to move down a [] gradient  Diffusion continues until there is NO [] gradient  Ex: O 2 diffuses into oxygen depleted blood

Diffusion Small molecules like WATER, OXYGEN, AND CARBON DIOXIDE can move in and out freely. Large molecules like PROTEINS AND CARBOHYDRATES CANNOT Charged IONS CANNOT

Video 2 Osmosis

Osmosis~ the diffusion of water across a selectively permeable membrane

Questions  Osmosis is the diffusion of _______ across a cell membrane.  Osmosis and Diffusion are both types of __________ transport.  Passive transport does or does not require energy?  Small molecules can not move across freely. T or F  Large molecules can move freely. T or F

Three Different Types of Solutions  Isotonic Solution  Hypotonic Solution  Hypertonic Solution

Isotonic Solution  The solute outside the cell is equal in concentration to the solute in the cell.  The cell retains its shape.  water moves equally in both directions

Hypotonic Solutions  Solution outside the blood cell contains a lower [] of solute than inside of the cell.  Water will diffuse in. l cell will lyse (burst).  Animal cells - cytolysis.  Plant cells do not burst- turgur pressure— grocers use this idea

Cells in a Hypotonic Solution

Hypertonic Solutions  The solution outside the cell has a higher [] of solute than inside of the cell.  Water will diffuse out of the cell, l causing the cell to shrink l or crenate  Why should you not salt meat before cooking? CRENATIONPLASMOLYSIS

Cells in a Hypertonic Solution

In what type of solution would these cells be found?

Water balance Summary  Osmoregulation ~ control of water balance  Hypertonic ~ higher concentration of solutes  Hypotonic ~ lower concentration of solutes  Isotonic ~ equal concentrations of solutes

Water balance Summary  Osmoregulation ~ control in cells with cell walls :  Turgid (very firm) - Hypo  Flaccid (limp) - Iso  Plasmolysis~ Hyper l plasma membrane pulls away from cell wall

Plasmolysis Turgidity

Other Ways to Transport Molecules Across the Plasma Membrane Selective Transport

Review Covered Passive Transport OO smosis DD oes it require energy? NN O!!! DD iffusion DD oes it require energy? NN O!!!

Osmosis  What is osmosis?  The movement of ___________ across the cell membrane.  Is it the movement of any other substance?  NO!!!! WATER

Diffusion  Mixing of two substances by the random motion of molecules.  Molecules move from a region of high concentration to an area of low concentration.

How do other molecules cross the cell membrane???  Selective Transport l Facilitated Diffusion (Another Passive Transport) l Active Transport Protein Pumps Endocytosis Exocytosis

Selective Transport  There are two types of selective transport l Facilitated Diffusion DOES NOT require the use of energy l Active Transport DOES require the use of energy

High Concentration Low Concentration Cell Membrane Glucose molecules Protein channel Facilitated Diffusion

 Does facilitated diffusion require the use of energy?  NO!!!!  It uses a [] gradient to transport molecules  The molecules move from an area of high [] to an area of low []  Most SUGAR molecules pass across the cell membrane by this method of transport

Carrier Proteins Carry Molecules Across the Membrane  Good Example - transport of Glucose into the Cell

Active Transport  Does active transport require the use of energy?  YES!!!  It uses ATP  Transports against the [] gradient.  Low to High []  Sodium Potassium Pump, Endocytosis and Exocytosis

Molecule to be carried Molecule being carried Energy Active Transport

Active Transport: Sodium Potassium Pump  Move Sodium out of the cell  Move Potassium into the cell  Uses energy (ATP)  Causes the protein to change shape  Move against a [] gradient

Sodium Potassium Pump

Bulk Transport-Active  Endocytosis l Pinocytosis l Phagocytosis  Exocytosis

Endocytosis  During ENDOCYTOSIS the Cell Membrane folds into a POUCH (Vescicle) that Encloses the Particles.

Two Types of Endocytosis: Pinocytosis and Phagocytosis  PINOCYTOSIS ---" CELL DRINKING “—Small Particles  PHAGOCYTOSIS---- " CELL EATING “-Large Particles

Treatments

Exocytosis  EXOCYTOSIS is the opposite OR reverse of ENDOCYTOSIS.  EXOCYTOSIS, wastes and cell products leave the cell.

Specialized Transport Summary  Transport proteins  Facilitated diffusion~ passage of molecules and ions with transport proteins across a membrane down the [] gradient  Active transport~ movement of a substance against its [] gradient with the help of cellular energy

Elaborate  Cell Membrane Bubbles  Cellular Transport Flow Chart