diffusion and osmosis
DESCRIPTION
Diffusion and osmosis. Weeee!!!. high. low. This is gonna be hard work!!. high. low. Types of Cellular Transport. Passive Transport cell doesn’t use energy Diffusion Facilitated Diffusion Osmosis Active Transport cell does use energy Protein Pumps Endocytosis Exocytosis. - PowerPoint PPT PresentationTRANSCRIPT
DIFFUSION AND OSMOSIS
Types of Cellular Transport
Passive Transport cell doesn’t use energy
1. Diffusion2. Facilitated Diffusion3. Osmosis
Active Transportcell does use energy
1. Protein Pumps2. Endocytosis3. Exocytosis
high
low
This is gonna
be hard work!!
high
low
Weeee!!!
Bacon Frying…
What do you smell?
Why do you smell this?
Bacon Frying…
• Fat droplets are released into the airsteam coming off of the bacon
• Causes the fat droplets (particles) to collide and disperse.
In science terms…• DIFFUSION IS OCCURING!
• The bacon fat droplets (particles) diffuse from the area of high concentration (directly above the frying pan), to areas of low concentration (the room)
• Continues until equilibrium is reached Particles equally distributed
throughout the space (room)
Diffusion
Diffusion - Defined as the movement of particles from areas of high concentration to areas of low concentration (down the concentration gradient) Particles spread out Ex: Solute = perfume Solvent = the air
Low Solute Concentration
High Solute Concentration
Diffusion
Diffusion rate (how fast it occurs) depends on:
1. Size- smaller molecules move more easily
2. Concentration- high concentration = faster spread
Ex: The more bacon you have (=more fat droplets released), the faster the smell will spread throughout the room
3. Temperature- high temps speed up the process
Which will cause the smell to disperse faster? Cold bacon in a frying pan and the stove is OFF
OR Bacon in a frying pan and the stove in ON
What is a semi-permeable membrane?
A membrane that allows certain molecules to pass through it by diffusion or osmosis
Think about a Ping-Pong net..
Which would pass through?
Osmosis
Diffusion that involves waterwater. Movement of water across a semi-
permeable membrane
Cell membranes are semi-permeable Water and some gases move through the
membrane easily, while larger molecules like proteins and sugars do not.
Cells must regulate- molecules move from internal environment to external environment (and vice versa) so that both environments have equal concentrations. Animation: How Osmosis Works
Osmosis
Diffusion that involves waterwater. Movement of water across a semi-
permeable membrane Water moves from areas of low
solute to areas of high solute
Why do your fingers “shrivel–up” when you are in the water?
Effects of Osmosis on Life
Osmosis- diffusion of water through a selectively permeable membrane.
There are 3 types of solutions (=Tonicity) 1.) Isotonic2.) Hypertonic3.) Hypotonic
Isotonic Solution
Solutions that contain the same concentration of solutes as the cytoplasm are called isotonic (or normal saline) solutions.
There is no net movement of water either into or out of the cell.
Cells maintain their normal shape.
WATCH VIDEO OF BLOOD IN AN ISOTONIC SOLUTION
Isotonic Solution
Isotonic Isotonic The concentration of solutes in the external solution is equal to the concentration of solutes inside the cell.
Result Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium)
• Osmosis Animations for
isotonic, hypertonic, and
hypotonic solutions
Hypertonic Solution
A hypertonic solution is a solution that contains more solutes than the cytoplasm of the cell. (hyper)
Has less water than the cell and water moves out of the cell. The cells shrink.
WATCH VIDEO OF NORMAL RBCs SUBJECTED TO A HYPERTONIC SOLUTION
Hypertonic Solution
Hypertonic: The solution has a higher concentration of solutes and a lower concentration of water than inside the cell. (High solute; Low water)
Result: Water moves from inside the cell into the solution: Cell shrinks (Plasmolysis/crenation)!
• Osmosis Animations for
isotonic, hypertonic, and
hypotonic solutions
shrinks
Hypotonic Solution
A hypotonic solution contains less solute (thus, more water) than the cytoplasm of the cells.
The water will move into the cells resulting in the swelling and lysis of the cells.
WATCH VIDEO OF CRENATED RBCs SUBJECTED TO A HYPOTONIC SOLUTION
Hypotonic Solution
Hypotonic: The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (Low solute; High water)
Result: Water moves from the solution to inside the cell): Cell Swells and bursts open (cytolysis)!
• Osmosis Animations for
isotonic, hypertonic, and
hypotonic solutions
Let’s take a closer look!
http://www.coolschool.ca/lor/BI12/unit4/U04L06/rbc.html
What type of solution are these cells in?
A CB
Hypertonic Isotonic Hypotonic
Tonicity
Used to compare different solutions Hypertonic- higher solute concentration
relative to another*think hyperactive
Hypotonic- lower solute concentration relative to another
*think hypothermia
Isotonic- equal solute concentrations between two solutions
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Cell in Isotonic SolutionCell in Isotonic Solution
CELLCELL
10% NaCL90% H2O
10% NaCL
90% H2O
What is the direction of water movement?
The cell is at _______________.equilibrium
ENVIRONMENTENVIRONMENT
NO NET NO NET MOVEMENTMOVEMENT
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Cell in Hypotonic Cell in Hypotonic SolutionSolution
CELLCELL
10% NaCL90% H2O
20% NaCL
80% H2O
What is the direction of water movement??
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Cell in Hypertonic Cell in Hypertonic SolutionSolution
CELLCELL
15% NaCL85% H2O
5% NaCL95% H2O
What is the direction of water movement?
ENVIRONMENTENVIRONMENT
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Cells in SolutionsCells in Solutions
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Isotonic Solution
NO NET MOVEMENT OF
H2O (equal amounts entering
& leaving)
Hypotonic Solution
CYTOLYSIS
Hypertonic Solution
PLASMOLYSIS
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Cytolysis & PlasmolysisCytolysis & Plasmolysis
Cytolysis Plasmolysis
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Osmosis in Red Blood Osmosis in Red Blood CellsCells
Isotonic Hypotonic
Hypertonic
What Happens to Blood Cells?
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