Question of the Day 12-7 Homeostasis = ??? What kind of solution can cause a cell to burst (explode)? isotonic, hypotonic, or hypertonic? Water crosses through a ________ ____________ __________ during osmosis.

Review

12-7 Lab Pages 6 and 7 questions

12-8 Question of the Day Get out a clean piece of paper you can turn in Questions: What is osmosis? What is a hypertonic solution? What happens to the cell in this type of solution? What is a hypotonic solution? What happens to the cell in this type of solution?

Control = 56.5 grams

12-8 Lab Notes Page 8

Contractile Vacuoles – Organelle that excretes excess water from cells Uses ATP Usually found in unicellular freshwater organisms. This prevents them from bursting in a hypotonic solution. 7

Contractile vacuole 8

Plasmolysis – loss of turgor pressure in plant cell due to loss of water What happens to a plant during plasmolysis? The plant wilts The plants plasma membrane and cytoplasm will shrink away from the cell wall 9

REVIEW: What will happen to an Elodea Leaf in a hypertonic solution? Water will leave the cell… …which is called playsmolsis, which will cause the plant leaves to wilt Cell membrane Cell membrane

Review If we put Elodea leaves in a hypotonic solution, what happens? Water will move into the cell…. ….which will cause the cell to swell. If it’s an animal cell it will…. …burst, UNLESS the cell has a Contractile vacuole to pump the water out. to Cell membrane pushing against the cell wall

Summary of Hypo/Hypertonic solution changes on a RBC. 12

Review If the cell shrinks, it is in what type of solution? If the cell is at equilibrium with it’s environment, its in what type of solution? If the cell swells, it’s in what type of solution? Water –90% Salt – 10% Water 95% Salt 5% Water 64% Salt 36% Water 44% Salt 56% Water 50% Salt 50% Water 50% Salt 50% 13

pages 6-7 assignment

Egg Lab Report Graph Add a column to you data table: Must be colored Starting Mass (grams) Final Mass (g) Change in mass (g) % Change in Mass ((Initial Mass – Final Mass) / Initial Mass) x 100 Egg in shell ===== ==== === Vinegar Corn Syrup Distilled Graph Must be colored Graph your starting mass and then use your final mass data which is in blue Add a column to you data table: “Percent Change in Mass” ((Initial Mass – Final Mass) / Initial Mass) x 100 Calculate all the changes in mass for your egg

Egg Lab Report Analysis of your Data: What you should turn in: Be sure you are using the terms we’ve discussed in class in your explanation of your results. Example What you should turn in: Page 1 – Directions Page 2 – Written lab report Page 3 – Graph Page 4 – Your actual lab procedure

Selective Permeability – plasma membrane to allows some materials to pass while keeping others out Why is selective permeability important? So the cell can allow important substance in (water, oxygen, glucose) and keep harmful substances out (bacteria).

Passive Transport This process uses no ATP Passive Transport – movement of particles across membranes by diffusion This process uses no ATP Molecules moving from hi concentration  low concentration

Facilitated Diffusion – name for passive transport using transport proteins Does not use energy!!! Example: Glucose going from high concentration outside cell low concentration inside the cell Why doesn’t this need energy? Because it’s still along the concentration gradient transport proteins

Transport / carrier proteins – proteins that assist facilitated diffusion

Ion channels are ion specific proteins transport ions from high concentration to lower concentration Ions like Na+, Ca+, etc are not soluble in lipids, so they must travel through proteins channels Ion channels are ion specific Some channels are always open, some have gate Gates open from stimuli: stretching of cell membrane electrical or chemical signals

Active Transport Active Transport – ATP (adenosine tri-phosphate) – transport of materials against a concentration gradient – requires energy ATP (adenosine tri-phosphate) – the ENERGY molecule for the cell Breaks down from ATP  ADP (Adenosine di-phosphate) Hydrolysis of the phosphate releases energy

Active Transport Example http://www. youtube. com/watch

Sodium-potassium Pump – transfer protein example Transfers Na+ out and K+ in Creates electrical gradient which is important for nerve impulses http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.html

Na+ / K+ Pump

Endocytosis – when a cell surrounds and takes in material from the environment Uses ATP

Endocytosis

Pinocytosis – Transport of fluids into the cell

Phagocytosis – Phagocytes – Transfer of large particles / cells into the cell Phagocytes – Cells that ingest bacteria / viruses and lysosomes fuse w/ vesicle to destroy them before harm done http://www.youtube.com/watch?v=1w10R9lv7eQ

Exocytosis – when a cell expels materials to the extracellular environment Cell exports proteins, hormones and wastes this way This process uses ___ATP___

Endo / Exocytosis

Exocytosis and endocytosis http://www.youtube.com/watch?v=K7yku3sa4Y8

The End

Warm Up 1-5 Draw and Label Each – hypotonic, hypertonic, isotonic, active transport, diffusion: (Blue circles = cells) NaCl 12% NaCl 25% NaCl 20% NaCl 35% Sugar 10% Sugar 5% ATP used

Dialysis Tubing Lab Groups of two or three (NOT 4) Read through part 1 – create a flow chart of the procedure

Warm Up 1-6 How is the dialysis tubing “selective”? Get out your dialysis tubing lab.

Warm Up 1-6 Get you Part II lab set up Make your observations – finish lab questions Turn in your lab. Today: Begin photosynthesis chapter

Warm Up 1-7 Get your Part II lab set up Make your observations Finish the lab questions – Turn in Lab Today: Start Photosynthesis!!

Hypo / Hypertonic Solutions