Cell Membrane HOMEOSTASIS: internal “steady state” maintained by the body 1. What is the cell membrane made of? Phospholipid bilayer Hydrophobic tails Hydrophilic head Phosphate head Fatty acid tails

II. Cell Membrane Homeostasis Selectively Permeable Steady state maintained by the body Selectively Permeable Regulates what can come in and out of the cell

1. Selectively Permeable CAN EASILY PASS: Small, Nonpolar O2 CO2 Water (only through protein channels) CANNOT EASILY PASS: Large (glucose) Polar ( exception is water because its so small) Ion (charged) Breathing Good breath in 02 we want it to get to all of our cells- done, Co2 to leave easily!!!! Demo 6.3 online activity

III. Proteins in the Cell Membrane “Fluid Mosaic Model” Many proteins will help the membrane Proteins drift freely

Membrane Proteins Embedded Transport Proteins Cell Recognition Proteins- sugars hang off proteins Receptors Proteins- receive signals Enzymes- proteins that make reactions happen Dopamine-

Cell Recognition Proteins Sugars hang off of proteins in the cell membrane Give us different blood types Vary between species, between types of cells, and even individuals Blood transfusion – red blood cells have different glycoproteins on them Example Xenotransplantation- An antigen is any substance that causes your immune system to produce antibodies Is the universal donor- no antigen on it no other blood type reactions ( can only accept O) AB blood can accept A blood, B blood, O blood

Receptor Protein Receptor Protein- is a cell membrane protein that receives a signal Finish with period 5- tomorrow they have lab

Transport Passive trasnport- no energy Active trasnport – energy

1. Passive Transport: Diffusion The movement of particles HIGH concentration to LOW concentration Why? Molecules are always in random motion Ex. Perfume Food coloring Tea bag On cold days must wear more molecule move slower- faster in the heat

b) Equilibrium- particles equally spread out

2. Passive Transport: Osmosis Diffusion of water from HIGH to LOW concentration Solute: Substance in solution that is dissolved (ex. Sugar or Salt) Solvent: Substance in solution that does the dissolving ( ex. Water)

Hypotonic Environment Hypertonic Environment Isotonic Environment TONICITY Hypotonic Environment Hypertonic Environment Isotonic Environment Don’t draw- have students fill out charts – print 4 pages

Isotonic Same “dynamic equilibrium” “homeostasis Diagram Where is the most water? Which way does water go? Result? Big words Examples 97% H20 97% H2O 97% H2O Same Inside and outside Even, same concentration overall http://wardmulroy.com/gatorade/DOCS/1/content(9).html Gatorade website “dynamic equilibrium” “homeostasis contact lens solution, Gatorade

Hypotonic Outside Inside Burst, get bigger; firm Diagram Where is the most water? Which way does water go? Result? Big words Examples 92 % H20 97% H2O Outside Inside Burst, get bigger; firm “cytolysis”- to burst; “turgid”- get firm; “turgor pressure” :pressure inside plant cells to help stand upright - Distilled water ( 100% Water) - Plants standing upright

There is a 20 second video of contractile vacuole attached to image There is also a short video of RBCs in pure water attached to image

Hypertonic Candy, sugar, salt on bushes/grass, gargle with salt water Diagram Where is the most water? Which way does water go? Result? Big words Examples 97% H20 80% Water Inside Outside Smaller, shrink, go limp HONORS CRENATION- means red blood cells shrink! “plasmolysis”- to wilt, shrivel, loss of pressure; “flaccid”- go limp Candy, sugar, salt on bushes/grass, gargle with salt water

Hypertonic Red Blood Cells Short 40 second video of RBCs shrinking in salt solution attached to picture WHY DOES SODA MAKE YOU MORE THIRSTY http://www.youtube.com/watch?v=PiQkebrCw8U-- salt a slug!!!!!

Check Yourself Is the lettuce in a hypertonic isotonic hypotonic environment and why?? Poll 6.3 online activity!! Page 1 and 2

Passive Transport: 3. Facilitated Diffusion diffusion across a membrane through transport proteins Ex. sugars, ions , alcohol b) NO ENERGY: From HIGH to LOW concentration

V. Active Transport Movement of molecules across a membrane require energy From LOW to HIGH concentrations! a) Why? To maintain a certain internal environment To transport large molecules in/out Remove salt from our cells

The water from soil moves into roots from HIGH to LOW The water from soil moves into roots from HIGH to LOW. But then eventually, the roots will have more water. To prevent the water from going back out, the tree uses ACTIVE TRANSPORT to keep pumping more water in. H2O H2O H2O H2O H2O H2O

Active Transport C) Some Types of Active Transport 1. Exocytosis Removal of materials Vesicle fuses with membrane, forcing contents out

Active Transport 2. Endocytosis process of taking in materials by infolding of the cell membrane, forming a vesicle Ex. Phagocytosis: Large particle/food Amoeba Amobea eats paramecium

6.3 animation- cell eat yeast

Active transport video- cystic fibrous

VI. Concentration Gradient measurement of how the concentration of something changes from one place to another Passive Transport: molecules go DOWN concentration gradient from HIGH to LOW concentration Active Transport: molecule go UP concentration gradient from LOW to HIGH concentration If I get to it

Example of DOWN concentration gradient: Students going from classrooms into hallways for next class Example of UP concentration gradient: At a concert, moving into the crowd towards crowded stage

Review Video of Transport Why does a plant like hypotonic but an animal does not? http://www.phschool.com/science/biology_place/labbench/lab1/watpot.html

Elodea Plasmolysis

http://www.youtube.com/watch?v=2Th0PuORsWY

“Egg”citing “Eggs”periment Cell membrane

Egg Lab: Osmosis