The Cell Membrane Gateway to the Cell The Plasma Membrane 11/28/2018 The Cell Membrane Gateway to the Cell G. Podgorski, Biol. 1010

The Plasma Membrane 11/28/2018 Cell Membrane The cell membrane is flexible and allows a unicellular organism to move G. Podgorski, Biol. 1010

copyright cmassengale Cell Membrane 1. Lipid bilayer with proteins imbedded throughout. 2. Controls what enters and leaves the cell. 3. Also known as the plasma membrane copyright cmassengale

copyright cmassengale Cell Transport The movement of liquid IN and OUT of the cell. The absorption and excretion of liquids. The purpose of moving things in and out is to achieve homeostasis. copyright cmassengale

Homeostasis Balanced internal condition of cells The Plasma Membrane 11/28/2018 Homeostasis Balanced internal condition of cells Also called equilibrium Maintained by plasma membrane controlling what enters & leaves the cell G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 11/28/2018 Tonicity If a solution has too much of something, we call it HYPERTONIC. Hyper=too much If a solution has too little of something, we call it HYPORTONIC. Hypo=too little copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale If a solution is balanced, we call it ISOTONIC. Iso=Equilibrium or Homeostasis copyright cmassengale

Types of Transport Across Cell Membranes The Plasma Membrane 11/28/2018 Types of Transport Across Cell Membranes copyright cmassengale G. Podgorski, Biol. 1010

Simple Diffusion Requires NO energy The Plasma Membrane 11/28/2018 Simple Diffusion Requires NO energy Molecules move from area of HIGH to LOW concentration G. Podgorski, Biol. 1010

The Plasma Membrane 11/28/2018 DIFFUSION Diffusion is a PASSIVE process which means no energy is used to make the molecules move, they have a natural KINETIC ENERGY G. Podgorski, Biol. 1010

Diffusion of Liquids The Plasma Membrane 11/28/2018 G. Podgorski, Biol. 1010

Diffusion through a Membrane The Plasma Membrane 11/28/2018 Diffusion through a Membrane Cell membrane Solute moves DOWN concentration gradient (HIGH to LOW) G. Podgorski, Biol. 1010

Diffusion across a membrane Semipermeable membrane The Plasma Membrane 11/28/2018 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 G. Podgorski, Biol. 1010

Diffusion of H2O Across A Membrane The Plasma Membrane 11/28/2018 Diffusion of H2O Across A Membrane High H2O potential Low solute concentration Low H2O potential High solute concentration G. Podgorski, Biol. 1010

Three Forms of Transport Across the Membrane The Plasma Membrane Three Forms of Transport Across the Membrane 11/28/2018 G. Podgorski, Biol. 1010

Passive Transport Simple Diffusion Doesn’t require energy The Plasma Membrane 11/28/2018 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. G. Podgorski, Biol. 1010

Facilitated diffusion The Plasma Membrane 11/28/2018 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. G. Podgorski, Biol. 1010

Active Transport Requires energy or ATP The Plasma Membrane 11/28/2018 Active Transport Requires energy or ATP Moves materials from LOW to HIGH concentration AGAINST concentration gradient G. Podgorski, Biol. 1010

Exocytosis- moving things out. The Plasma Membrane Moving the “Big Stuff” 11/28/2018 Exocytosis- moving things out. 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. G. Podgorski, Biol. 1010

The Plasma Membrane Moving the “Big Stuff” 11/28/2018 Large molecules move materials into the cell by one of three forms of endocytosis. G. Podgorski, Biol. 1010

Pinocytosis Cell forms an invagination The Plasma Membrane 11/28/2018 Pinocytosis Cell forms an invagination Materials dissolve in water to be brought into cell Called “Cell Drinking” G. Podgorski, Biol. 1010

Receptor-Mediated Endocytosis The Plasma Membrane 11/28/2018 Receptor-Mediated Endocytosis Some integral proteins have receptors on their surface to recognize & take in hormones, cholesterol, etc. G. Podgorski, Biol. 1010

Endocytosis – Phagocytosis The Plasma Membrane 11/28/2018 Endocytosis – Phagocytosis Used to engulf large particles such as food, bacteria, etc. into vesicles Called “Cell Eating” G. Podgorski, Biol. 1010

Phagocytosis About to Occur The Plasma Membrane Phagocytosis About to Occur 11/28/2018 G. Podgorski, Biol. 1010

The Plasma Membrane 11/28/2018 Phagocytosis - Capture of a Yeast Cell (yellow) by Membrane Extensions of an Immune System Cell (blue) G. Podgorski, Biol. 1010

copyright cmassengale Solvent or Solution The substance doing the dissolving Example water is a solvent in kool-aid copyright cmassengale

copyright cmassengale Solute The thing being dissolved Example sugar is a solute in kool-aid copyright cmassengale

copyright cmassengale WATER ALWAYS FOLLOWS THE HIGHEST SOLUTE! copyright cmassengale

copyright cmassengale Isotonic When the percent of solute is the same inside and outside of the cell. Causes no net movement between the cell membrane. copyright cmassengale

Cell in Isotonic Solution The Plasma Membrane 11/28/2018 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 _______________. G. Podgorski, Biol. 1010

copyright cmassengale Hypotonic Water moves into the cell because there is more solute in the cell copyright cmassengale

Cell in Hypotonic Solution The Plasma Membrane 11/28/2018 Cell in Hypotonic Solution 10% NaCL 90% H2O CELL 20% NaCL 80% H2O What is the direction of water movement? G. Podgorski, Biol. 1010

copyright cmassengale Hypertonic Water moves out of the cell because there is more solute outside of the cell copyright cmassengale

Cell in Hypertonic Solution The Plasma Membrane 11/28/2018 Cell in Hypertonic Solution 15% NaCL 85% H2O ENVIRONMENT CELL 5% NaCL 95% H2O What is the direction of water movement? G. Podgorski, Biol. 1010

copyright cmassengale The water always follows the highest solute number. copyright cmassengale

copyright cmassengale Watch this Video! Click to Watch Osmosis Video! copyright cmassengale

Cells in Solutions The Plasma Membrane 11/28/2018 G. Podgorski, Biol. 1010

NO NET MOVEMENT OF H2O (equal amounts entering & leaving) The Plasma Membrane 11/28/2018 Isotonic Solution Hypotonic Solution Hypertonic Solution NO NET MOVEMENT OF H2O (equal amounts entering & leaving) CYTOLYSIS PLASMOLYSIS G. Podgorski, Biol. 1010

Cytolysis & Plasmolysis The Plasma Membrane 11/28/2018 Cytolysis & Plasmolysis Cytolysis Plasmolysis G. Podgorski, Biol. 1010

Osmosis in Red Blood Cells The Plasma Membrane 11/28/2018 Osmosis in Red Blood Cells Isotonic Hypertonic Hypotonic G. Podgorski, Biol. 1010

isotonic hypotonic hypertonic hypertonic isotonic hypotonic The Plasma Membrane 11/28/2018 isotonic hypotonic hypertonic hypertonic isotonic hypotonic G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 11/28/2018 copyright cmassengale G. Podgorski, Biol. 1010