Types of Transport Across Cell Membranes Chapter 8 The Plasma Membrane 5/20/2018 Types of Transport Across Cell Membranes Chapter 8 copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 5/20/2018 1. 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 5/20/2018 DIFFUSION Diffusion is a PASSIVE process which means no energy is used to make the molecules move copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 5/20/2018 Diffusion of Liquids copyright cmassengale G. Podgorski, Biol. 1010

Diffusion across a membrane Semipermeable membrane The Plasma Membrane 5/20/2018 2. 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

Cell in Isotonic Solution Cell stays the same size The Plasma Membrane 5/20/2018 Cell in Isotonic Solution Cell stays the same size 10% NaCL 90% H2O ENVIRONMENT CELL NO NET MOVEMENT 10% NaCL 90% H2O copyright cmassengale G. Podgorski, Biol. 1010

Cell in Hypotonic Solution Cell Swells The Plasma Membrane 5/20/2018 Cell in Hypotonic Solution Cell Swells 10% NaCL 90% H2O CELL 20% NaCL 80% H2O Water moves into the cell copyright cmassengale G. Podgorski, Biol. 1010

Cell in Hypertonic Solution cell shrinks The Plasma Membrane 5/20/2018 Cell in Hypertonic Solution cell shrinks 15% NaCL 85% H2O ENVIRONMENT CELL 5% NaCL 95% H2O ?Water comes out of the cell copyright cmassengale G. Podgorski, Biol. 1010

NO NET MOVEMENT OF H2O (equal amounts entering & leaving) The Plasma Membrane 5/20/2018 Isotonic Solution Hypotonic Solution Hypertonic Solution NO NET MOVEMENT OF H2O (equal amounts entering & leaving) Cell swells Cell shrinks copyright cmassengale G. Podgorski, Biol. 1010

Osmosis in Red Blood Cells The Plasma Membrane 5/20/2018 Osmosis in Red Blood Cells Isotonic Hypertonic Hypotonic copyright cmassengale G. Podgorski, Biol. 1010

3. Facilitated diffusion The Plasma Membrane 5/20/2018 3. 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

Facilitated Diffusion The Plasma Membrane 5/20/2018 Facilitated Diffusion Molecules will randomly move through the pores in Channel Proteins. copyright cmassengale G. Podgorski, Biol. 1010

Facilitated Diffusion The Plasma Membrane 5/20/2018 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

copyright cmassengale The Plasma Membrane 5/20/2018 4. 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 5. Exocytosis-Cells get rid of substances Example: Glands secreting 5/20/2018 Gland forming vesicle to get rid of a secretion. copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 6. Endocytosis: cell takes in substances. 5/20/2018 Example of endocytosis- White blood cell takes in bacteria to destroy copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 5/20/2018 Endocytosis – Phagocytosis Used to engulf large particles such as food, bacteria, etc. into vesicles Called “Cell Eating” copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale

copyright cmassengale The Plasma Membrane Phagocytosis About to Occur (This is a white blood cell) 5/20/2018 copyright cmassengale G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 5/20/2018 Phagocytosis - Capture of a Yeast Cell (yellow) by Membrane Extensions of a White Blood Cell (blue) copyright cmassengale G. Podgorski, Biol. 1010