copyright cmassengale The Plasma Membrane 12/6/2018 The Plasma Membrane - Gateway to the Cell copyright cmassengale G. Podgorski, Biol. 1010

Structure of the Cell Membrane The Plasma Membrane 12/6/2018 Structure of the Cell Membrane copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale Membrane Components The Plasma Membrane 12/6/2018 Phospholipids Proteins (peripheral and integral) Cholesterol copyright cmassengale Carbohydrates (glucose) 3 G. Podgorski, Biol. 1010 3

Stop and Sketch!

copyright cmassengale The Plasma Membrane 12/6/2018 Cell Membrane The cell membrane is flexible and allows a unicellular organism to move copyright cmassengale G. Podgorski, Biol. 1010

Functions of Plasma Membrane The Plasma Membrane 12/6/2018 Functions of Plasma Membrane Protective barrier Regulate transport in & out of cell (selectively permeable) Allow cell recognition Provide anchoring sites for filaments of cytoskeleton copyright cmassengale G. Podgorski, Biol. 1010

Functions of Plasma Membrane The Plasma Membrane 12/6/2018 Functions of Plasma Membrane Provide a binding site for enzymes Interlocking surfaces bind cells together (junctions) Contains the cytoplasm (fluid in cell) copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale Membrane Components The Plasma Membrane 12/6/2018 Phospholipids Proteins (peripheral and integral) Cholesterol copyright cmassengale Carbohydrates (glucose) G. Podgorski, Biol. 1010

copyright cmassengale

copyright cmassengale The Plasma Membrane 12/6/2018 Phospholipids A Phospholipid bi-layer makes up most of the cell membrane Contains 2 fatty acid chains that are nonpolar Head is polar & contains a –PO4 group & glycerol copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 FLUID MOSAIC MODEL FLUID- because individual phospholipids and proteins can move side-to-side within the layer, like it’s a liquid. MOSAIC- because of the pattern produced by the scattered protein molecules when the membrane is viewed from above. copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane Cell Membrane 12/6/2018 Polar heads are hydrophilic “water loving” Nonpolar tails are hydrophobic “water fearing” Makes membrane “Selective” in what crosses copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane Cell Membrane 12/6/2018 The cell membrane is made of 2 layers of phospholipids called the lipid bilayer Hydrophobic molecules pass easily; hydrophilic DO NOT copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Solubility Materials that are soluble in lipids can pass through the cell membrane easily copyright cmassengale G. Podgorski, Biol. 1010

Semipermeable Membrane The Plasma Membrane Semipermeable Membrane 12/6/2018 Small molecules and larger hydrophobic molecules move through easily. e.g. O2, CO2, H2O copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane Semipermeable Membrane 12/6/2018 Ions, hydrophilic molecules larger than water, and large molecules such as proteins do not move through the membrane on their own. copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Homeostasis Balanced internal condition of cells Also called equilibrium Maintained by plasma membrane controlling what enters & leaves the cell copyright cmassengale G. Podgorski, Biol. 1010

Types of Transport Across Cell Membranes The Plasma Membrane 12/6/2018 Types of Transport Across Cell Membranes copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Simple Diffusion Requires NO energy Molecules move from area of HIGH to LOW concentration copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 DIFFUSION Diffusion is a PASSIVE process which means no energy is used to make the molecules move, they have a natural KINETIC ENERGY copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Diffusion of Liquids copyright cmassengale G. Podgorski, Biol. 1010

Diffusion through a Membrane The Plasma Membrane 12/6/2018 Diffusion through a Membrane Cell membrane Solute moves DOWN concentration gradient (HIGH to LOW) copyright cmassengale G. Podgorski, Biol. 1010

Diffusion across a membrane Semipermeable membrane The Plasma Membrane 12/6/2018 Osmosis Diffusion across a membrane Diffusion of water across a membrane Moves from HIGH water potential (low solute) to LOW water potential (high solute) Semipermeable membrane copyright cmassengale G. Podgorski, Biol. 1010

Diffusion of H2O Across A Membrane The Plasma Membrane 12/6/2018 Diffusion of H2O Across A Membrane High H2O potential Low solute concentration Low H2O potential High solute concentration copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale Get into groups of 3 or 4 In the owl book, write down the definitions for facilitated diffusion, hypotonic, hypertonic, and isotonic. Give an example of each (may have to look this up on a device). copyright cmassengale

copyright cmassengale The Plasma Membrane 12/6/2018 Aquaporins Water Channels Protein pores used during OSMOSIS WATER MOLECULES copyright cmassengale G. Podgorski, Biol. 1010

Facilitated diffusion The Plasma Membrane 12/6/2018 Passive Transport Facilitated diffusion Doesn’t require energy Uses transport proteins to move high to low concentration Examples: Glucose or amino acids moving from blood into a cell. copyright cmassengale G. Podgorski, Biol. 1010

Proteins Are Critical to Membrane Function The Plasma Membrane 12/6/2018 Proteins Are Critical to Membrane Function copyright cmassengale G. Podgorski, Biol. 1010

Types of Transport Proteins The Plasma Membrane 12/6/2018 Types of Transport Proteins Channel proteins are embedded in the cell membrane & have a pore for materials to cross Carrier proteins can change shape to move material from one side of the membrane to the other copyright cmassengale G. Podgorski, Biol. 1010

Facilitated Diffusion The Plasma Membrane 12/6/2018 Facilitated Diffusion Molecules will randomly move through the pores in Channel Proteins. copyright cmassengale G. Podgorski, Biol. 1010

Facilitated Diffusion The Plasma Membrane 12/6/2018 Facilitated Diffusion Some Carrier proteins do not extend through the membrane. They bond and drag molecules through the lipid bilayer and release them on the opposite side. copyright cmassengale G. Podgorski, Biol. 1010

Cell in Isotonic Solution The Plasma Membrane 12/6/2018 Cell in Isotonic Solution 10% NaCL 90% H2O ENVIRONMENT CELL NO NET MOVEMENT 10% NaCL 90% H2O What is the direction of water movement? equilibrium The cell is at _______________. copyright cmassengale G. Podgorski, Biol. 1010

Cell in Hypotonic Solution The Plasma Membrane 12/6/2018 Cell in Hypotonic Solution 10% NaCL 90% H2O CELL 20% NaCL 80% H2O What is the direction of water movement? copyright cmassengale G. Podgorski, Biol. 1010

Cell in Hypertonic Solution The Plasma Membrane 12/6/2018 Cell in Hypertonic Solution 15% NaCL 85% H2O ENVIRONMENT CELL 5% NaCL 95% H2O What is the direction of water movement? copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Cells in Solutions copyright cmassengale G. Podgorski, Biol. 1010

NO NET MOVEMENT OF H2O (equal amounts entering & leaving) The Plasma Membrane 12/6/2018 Isotonic Solution Hypotonic Solution Hypertonic Solution NO NET MOVEMENT OF H2O (equal amounts entering & leaving) CYTOLYSIS PLASMOLYSIS copyright cmassengale G. Podgorski, Biol. 1010

Cytolysis & Plasmolysis The Plasma Membrane 12/6/2018 Cytolysis & Plasmolysis copyright cmassengale Cytolysis Plasmolysis G. Podgorski, Biol. 1010

Osmosis in Red Blood Cells The Plasma Membrane 12/6/2018 Osmosis in Red Blood Cells Isotonic Hypertonic Hypotonic copyright cmassengale G. Podgorski, Biol. 1010

What Happens to Blood Cells? copyright cmassengale

copyright cmassengale The Plasma Membrane 12/6/2018 isotonic hypotonic hypertonic hypertonic isotonic hypotonic copyright cmassengale G. Podgorski, Biol. 1010

With your group: Each person contribute a thought about what he/she has read (the topic you became an expert on). 2. Simulate your process using the shapes and the scenario provided.

With your group: Get yourselves ready to teach the class your membrane transport type using the scenario that I gave you yesterday! Make sure that all students can simulate the process!!!

Three Forms of Transport Across the Membrane The Plasma Membrane Three Forms of Transport Across the Membrane 12/6/2018 copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Passive Transport Simple Diffusion Doesn’t require energy Moves high to low concentration Example: Oxygen or water diffusing into a cell and carbon dioxide diffusing out. copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Carrier Proteins Other carrier proteins change shape to move materials across the cell membrane copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Active Transport Requires energy or ATP Moves materials from LOW to HIGH concentration AGAINST concentration gradient copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Active transport Examples: Pumping Na+ (sodium ions) out and K+ (potassium ions) in against strong concentration gradients. Called Na+-K+ Pump copyright cmassengale G. Podgorski, Biol. 1010

Sodium-Potassium Pump The Plasma Membrane 12/6/2018 Sodium-Potassium Pump 3 Na+ pumped out for every 2 K+ pumped in; creates a membrane potential copyright cmassengale G. Podgorski, Biol. 1010

Sodium-Potassium Pump – Another Animation highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.htmlhttp://

copyright cmassengale The Plasma Membrane Moving the “Big Stuff” 12/6/2018 Exocytosis- moving things out like wastes, mucus, or other cell products Molecules are moved out of the cell by vesicles that fuse with the plasma membrane. This is how many hormones are secreted and how nerve cells communicate with one another. copyright cmassengale G. Podgorski, Biol. 1010

Exocytosis –Another Example Proteins made by ribosomes are packaged into transport vesicles by the Golgi App; the vesicles fuse with the CM and then the proteins are secreted out of the cell.

Paramecium http://www.youtube.com/watch?NR=1&v=9Ynm5ZOW59Q These unicellular Protists use energy to pump out excess water by using a contractile vacuole

copyright cmassengale The Plasma Membrane Exocytosis 12/6/2018 Exocytic vesicle immediately after fusion with plasma membrane. copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane Moving the “Big Stuff” 12/6/2018 Large molecules move materials into the cell by one of three forms of Endocytosis. copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane Pinocytosis – http://www.youtube.com/watch?v=v8XaY-vVtcA 12/6/2018 Most common form of endocytosis. Takes in dissolved molecules as a vesicle. copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 1. Pinocytosis Cell forms an indention in the membrane; it “gulps” droplets of extracellular fluid Materials dissolve in water to be brought into cell; it’s really not the water the cell needs, it’s the molecules dissolved in the droplets Called “Cell Drinking” copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 1. Example of Pinocytosis 12/6/2018 mature transport vesicle pinocytic vesicles forming copyright cmassengale Transport across a capillary cell (blue). G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 2. Receptor-Mediated Endocytosis Some integral proteins have receptors (Glycoproteins!) on their surface to recognize & take in hormones, cholesterol, etc. copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 2. Receptor-Mediated Endocytosis http://www.youtube.com/watch?v=PifagmJRLZ0 12/6/2018 copyright cmassengale G. Podgorski, Biol. 1010

2. Receptor-Mediated Animation copyright cmassengale

copyright cmassengale The Plasma Membrane 12/6/2018 Endocytosis – 3. Phagocytosis Used to engulf large particles such as food, bacteria, etc. into vesicles Called “Cell Eating” copyright cmassengale G. Podgorski, Biol. 1010

Phagocytosis- Amoeba Feeding White Blood Cell Chasing Bacteria http://www.youtube.com/watch?NR=1&v=aWItglvTiLc http://www.youtube.com/watch?v=ojrkxmD6tT8&feature=related White Blood Cell Chasing Bacteria http://www.youtube.com/watch?v=KxTYyNEbVU4&feature=related

3. Phagocytosis Animation – copyright cmassengale

copyright cmassengale The Plasma Membrane Phagocytosis About to Occur 12/6/2018 copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Phagocytosis - Capture of a Yeast Cell (yellow) by Membrane Extensions of an Immune System Cell (blue) copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 12/6/2018 Exocytosis The opposite of endocytosis is exocytosis. Large molecules that are manufactured in the cell are released through the cell membrane. Inside Cell copyright cmassengale Cell environment G. Podgorski, Biol. 1010