D.N.A Objective: Compare isotonic, hypertonic, and hypotonic solutions, and predict the path of water and solutes in given examples through a lab Root Word: Hypo-Below 1. Which of the following correctly matches an organelle with its function? A. Mitochondria – photosynthesis B. Nucleus – cellular respiration C. Ribosome – manufacture of lipids D. Lysosome-movement E. Central vacuole – storage 2. A cell possesses ribosomes, a plasma membrane, a cell wall, and other parts. If could not be A. Bacterium B. A cell from a fungus C. A cell from a mouse D. An oak tree cell E. A bacterium or a cell from a pine tree

D.N.A Objective: SWBAT compare isotonic, hypertonic, and hypotonic solutions, and predict the path of water and solutes in given examples through a laboratory simulation Using your knowledge of osmosis/diffusion, what makes a french fry so crispy?

Exploration Question In your same lab group as yesterday, discuss a basic experimental design/procedure to test how to make crispy fries using your knowledge on osmosis/diffusion Materials: Potatoes, Salt, Water

Osmosis Through A Membrane Things to consider: What is your experimental hypothesis? What results to expect to occur to the dialysis bags under different environments (water/sucrose)?

Osmosis in A Plant Cell Things to consider: When using your microscope, first focus on the specimen on the lowest power, then switch to the highest power

3. If the nucleus is a cell’s “control center”, and chloroplasts its “solar collectors,” which of the following might be called the cell’s garbage disposer? A. Lysosome B. Golgi apparatus C. Flagellum D. Ribosome E. Nucleolus

Movement across the Cell Membrane 2007-2008

How do things move across the membrane? All living cells exist in a liquid environment Even the cells inside of plants in the desert!

Concentration gradient The liquid inside of cell (cytoplasm) and the liquid outside of the cell is not pure water, it has different particles dissolved into it A solution

Concentration Gradient Concentration is the measure of how many particles are dissolved in the liquid High concentration = more particles Low concentration = less particles

Concentration Gradient HIGH CONCENTRATION LOW CONCENTRATION Dissolved Particle Dissolved Particle

1st type of transport: Diffusion movement of particles from HIGH  LOW concentration Movement from high concentration of that substance to low concentration of that substance.

Simple Diffusion Move from HIGH to LOW concentration movement of water “passive transport” no energy needed movement of water diffusion osmosis

Facilitated Diffusion Diffusion through protein channels channels move specific molecules across cell membrane no energy needed facilitated = with help open channel = fast transport HIGH LOW Donuts! Each transport protein is specific as to the substances that it will translocate (move). For example, the glucose transport protein in the liver will carry glucose from the blood to the cytoplasm, but not fructose, its structural isomer. Some transport proteins have a hydrophilic channel that certain molecules or ions can use as a tunnel through the membrane -- simply provide corridors allowing a specific molecule or ion to cross the membrane. These channel proteins allow fast transport. For example, water channel proteins, aquaporins, facilitate massive amounts of diffusion. “The Bouncer”

2nd type of transport: Active Transport Cells may need to move molecules AGAINST concentration gradient conformational shape change transports solute from one side of membrane to other protein “pump” “costs” energy = ATP conformational change LOW HIGH Some transport proteins do not provide channels but appear to actually translocate the solute-binding site and solute across the membrane as the protein changes shape. These shape changes could be triggered by the binding and release of the transported molecule. This is model for active transport. ATP “The Doorman”

Getting through cell membrane Passive Transport Simple diffusion HIGH  LOW concentration gradient Facilitated transport through a protein channel Active transport diffusion against concentration gradient LOW  HIGH uses a protein pump requires ATP (energy) ATP

Transport summary simple diffusion facilitated diffusion ATP active transport

How about large molecules? Moving large molecules into & out of cell through vesicles & vacuoles endocytosis phagocytosis = “cellular eating” pinocytosis = “cellular drinking” exocytosis exocytosis

The movement of big particles INTO the cell Endocytosis The movement of big particles INTO the cell The cell actually engulfs the particles and brings them into the cell

ENDOCYTOSIS Protist eating another Animation from: http://academic.brooklyn.cuny.edu/biology/bio4fv/page/cell-movement.html Protist eating another http://www.accs.net/users/kriel/chapter%20nine/

The movement of big particles INTO the cell Endocytosis The movement of big particles INTO the cell The cell actually engulfs the particles and brings them into the cell

The movement of big particles OUT of the cell EXOCYTOSIS The movement of big particles OUT of the cell

The Special Case of Water Movement of water across the cell membrane 2007-2008

Osmosis is just diffusion of water Water is very important to life, so we talk about water separately Diffusion of water from HIGH concentration of water to LOW concentration of water across a semi-permeable membrane

Osmosis Water likes to move to the area where there are MORE particles Water will move until the number of water particles is equal to the dissolved particles Direction of water movement

Concentration of water Direction of osmosis is determined by comparing total solute concentrations Hypertonic - more solute, less water Hypotonic - less solute, more water Isotonic - equal solute, equal water hypotonic hypertonic water net movement of water

Water entering = water leaving ISOTONIC (“Same strength”): EQUAL OUTSIDE AND INSIDE Cells try to “maintain stable internal conditions = ____________________ http://bioweb.wku.edu/courses/biol121/Osmosis/Osmosis.asp HOMEOSTASIS Water entering = water leaving

swell and possibly burst Animation from: http://www.ouhscphysio.org/humanphys/animations/osmosis3.swf OSMOSIS HYPOTONIC (“Below strength”): Concentration outside cell is ________________ inside the cell More water enters than leaves cell so cell will ___________________ LESS THAN swell and possibly burst

OSMOSIS shrinks GREATER THAN Animation from: http://www.ouhscphysio.org/humanphys/animations/osmosis4.swf OSMOSIS HYPERTONIC (“Above Strength): Concentration outside cell is ____________________ inside cell More water leaves cell than enters so cell ____________ GREATER THAN shrinks Choose Blood Hypertonic link

Managing water balance Cell survival depends on balancing water uptake & loss freshwater balanced saltwater

Osmotic Pressure

CFUs! WATER Is the solution that the cell is it hypertonic or hypotonic? Where does the water want to go? IN OR OUT OF THE CELL What will eventually happen to the cell? BURST!

CFUs! Is the solution that the cell is is hypertonic or hypotonic? Where does the water want to go? IN OR OUT OF THE CELL What will eventually happen to the cell? SHRINK!

Do you understand Osmosis… Cell (compared to beaker)  hypertonic or hypotonic Beaker (compared to cell)  hypertonic or hypotonic Which way does the water flow?  in or out of cell

Any Questions??