I. The Cell Membrane Gateway to the Cell The Plasma Membrane 1/18/2019 I. The Cell Membrane Gateway to the Cell G. Podgorski, Biol. 1010

Photograph of a Cell Membrane The Plasma Membrane 1/18/2019 Photograph of a Cell Membrane G. Podgorski, Biol. 1010

A. What does it do? Surrounds the cell The Plasma Membrane 1/18/2019 A. What does it do? Surrounds the cell Maintains homeostasis: controls what enters & leaves the cell (semi-permeable) a. Hormones, food waste, etc G. Podgorski, Biol. 1010

copyright cmassengale The Plasma Membrane 1/18/2019 2. What is it made of? copyright cmassengale G. Podgorski, Biol. 1010

II. What is it made of? Phospholipids Proteins The Plasma Membrane 1/18/2019 II. What is it made of? Phospholipids Proteins G. Podgorski, Biol. 1010

II. Types of Transport Across Cell Membranes The Plasma Membrane 1/18/2019 II. Types of Transport Across Cell Membranes G. Podgorski, Biol. 1010

Movement substances across a cell membrane: A. Passive Transport Movement substances across a cell membrane: From HIGH to LOW amounts (concentrations) Uses NO energy

1. Diffusion Requires NO energy The Plasma Membrane 1. Diffusion 1/18/2019 Requires NO energy Gasses and small molecules move from area of HIGH to LOW concentration G. Podgorski, Biol. 1010

Diffusion of Food Coloring The Plasma Membrane 1/18/2019 Diffusion of Food Coloring G. Podgorski, Biol. 1010

Diffusion through a Membrane The Plasma Membrane 1/18/2019 Diffusion through a Membrane Cell membrane Solute moves DOWN concentration gradient (HIGH to LOW) G. Podgorski, Biol. 1010

Check for understanding copyright cmassengale

2. Osmosis Movement of water across a membrane The Plasma Membrane 2. Osmosis 1/18/2019 Movement of water across a membrane Moves from HIGH water amount (low solute) to LOW water amount (high solute) High H2O amount Low solute concentration Low H2O amount High solute concentration G. Podgorski, Biol. 1010

a. Isotonic Solution The cell stays the same CELL 10% NaCL 90% H2O The Plasma Membrane 1/18/2019 10% NaCL 90% H2O ENVIRONMENT CELL NO NET MOVEMENT 10% NaCL 90% H2O What is the direction of water movement? The cell stays the same G. Podgorski, Biol. 1010

b. HypOtonic Solution The cell will SWELL CELL 10% NaCL 90% H2O The Plasma Membrane 1/18/2019 b. HypOtonic Solution 10% NaCL 90% H2O CELL 20% NaCL 80% H2O What is the direction of water movement? The cell will SWELL G. Podgorski, Biol. 1010

c. Hypertonic Solution The cell will SHRINK CELL 15% NaCL 85% H2O The Plasma Membrane 1/18/2019 15% NaCL 85% H2O ENVIRONMENT CELL 5% NaCL 95% H2O What is the direction of water movement? The cell will SHRINK G. Podgorski, Biol. 1010

NO NET MOVEMENT OF H2O (equal amounts entering & leaving) The Plasma Membrane 1/18/2019 Isotonic Solution Hypotonic Solution Hypertonic Solution NO NET MOVEMENT OF H2O (equal amounts entering & leaving) CELL SWELLS CELL SHRINKS G. Podgorski, Biol. 1010

Osmosis in Red Blood Cells The Plasma Membrane 1/18/2019 Osmosis in Red Blood Cells Isotonic Hypertonic Hypotonic G. Podgorski, Biol. 1010

1. What type of solution is Cell A? 2. What will happen to cell A?

3. Facilitated Diffusion The Plasma Membrane 1/18/2019 3. Facilitated Diffusion Doesn’t require energy Uses transport proteins to move from an area of high to low concentration Examples: Glucose or amino acids moving from blood into a cell. G. Podgorski, Biol. 1010

Facilitated Diffusion The Plasma Membrane 1/18/2019 Facilitated Diffusion Molecules will randomly move through the pores in Channel Proteins. copyright cmassengale G. Podgorski, Biol. 1010

Facilitated Diffusion The Plasma Membrane 1/18/2019 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. G. Podgorski, Biol. 1010

Facilitated Diffusion The Plasma Membrane 1/18/2019 Facilitated Diffusion Other carrier proteins change shape to move materials across the cell membrane G. Podgorski, Biol. 1010

B. ACTIVE TRANSPORT

Active Transport Requires energy or ATP The Plasma Membrane 1/18/2019 Active Transport Requires energy or ATP Moves materials from LOW to HIGH concentration AGAINST the flow (concentration gradient) G. Podgorski, Biol. 1010

Three Forms of Transport Across the Membrane The Plasma Membrane Three Forms of Transport Across the Membrane 1/18/2019 G. Podgorski, Biol. 1010

Check for understanding Which Protein would be used? What type of transport is this?

C. BULK MOVEMENT Movement of BIG, BULKY molecules Requires ENERGY

1. EXOCYTOSIS- moving bulky things out of the cell. The Plasma Membrane 1/18/2019 1. EXOCYTOSIS- moving bulky things out of the cell. G. Podgorski, Biol. 1010

Exocytosis Inside Cell Cell environment The Plasma Membrane 1/18/2019 G. Podgorski, Biol. 1010

The Plasma Membrane Exocytosis 1/18/2019 Exocytic vesicle immediately after fusion with plasma membrane. G. Podgorski, Biol. 1010

ENDOCYTOSIS- Large molecules move into the cell. The Plasma Membrane 1/18/2019 ENDOCYTOSIS- Large molecules move into the cell. G. Podgorski, Biol. 1010

The Plasma Membrane 1/18/2019 ENDOCYTOSIS G. Podgorski, Biol. 1010

ENDOCYTOSIS About to Occur The Plasma Membrane ENDOCYTOSIS About to Occur 1/18/2019 G. Podgorski, Biol. 1010

The Plasma Membrane 1/18/2019 Endocytosis- Capture of a Yeast Cell (yellow) by Membrane Extensions of an Immune System Cell (blue) G. Podgorski, Biol. 1010