 BellRinger ◦ review the definitions for the following terms from the “molecular movement” reading *Diffusion *Concentration gradient *Entropy ◦ Create a sentence explaining why you will smell my air freshener across the room (use the terms above)  Objectives ◦ Explain how cells respond in various solutions  Homework ◦ Revise your lab report conclusion if necessary ◦ Review notes for a short vocab quiz tomorrow  Solutions, solute, solvent, isotonic, hypertonic, hypotonic, osmosis diffusion, conc. gradient

 Molecular Movement p  Diffusion Video Diffusion

 Universe tends towards disorder (entropy) ◦ 2nd Law of Thermodynamics ◦ Particles in highly concentrated areas will disperse into a lower concentrated area

 Occurs “passively”- without energy, because it follows the 2 nd law of thermodynamics diffusionosmosis movement of water  Diffusion  movement of solutes from high  low concentration  Diffusion  movement of solutes from high  low concentration

 Water is very important to life, so we talk about water separately  Diffusion of water from high concentration of water (low solutes) to low concentration of water (high solutes) ◦ across a semi-permeable membrane

 How do we know which way osmosis will occur?  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 hypotonichypertonic water net movement of water

freshwaterbalancedsaltwater  Cell survival depends on balancing water uptake & loss

 Explain why you get thirsty when you eat a bucket of salty popcorn (Hint: think about what is happening to your cells). ◦ Use the following terms in your explanation  Concentration  Hypertonic  Osmosis  Solution

 Purpose  1 full paragraph describing why you are doing the project, why the information is important and how it will be useful to others  Question  Testable question that includes ind & dep variable and the conditions of testing  Hypothesis  If/then statement that includes both the ind & dep variables as well as reasoning  Materials  Must list quantities in metric units  Procedure  Explains how you are changing the ind variable  Explains how you are measuring the dep variable and exactly what data you are recording  So detailed that my grandmother could repeat it.  Have at least 3 people read your procedure and attempt to explain how they would do the experiment. (without your help) Would they collect the same data that you will?

 On loose-leaf 1. Identify the independent and dependant variables in your experiment 2. Set up the x & y axis of a graph using your variables 3. Fill in sample data on the graph based on your hypothesis 4. Describe the data you expect to collect based on your hypothesis(don’t analyze it, just describe it)

 BellRinger ◦ Vocab Quiz  Objectives ◦ Explain why diffusion and osmosis is important in the human body  Homework  Read the essay “Making Exchanges..” p  Write a story about a red blood cell traveling through the body. Explain where the cell goes and what types of substances are exchanged in the blood.

 Explain why you get thirsty when you eat a bucket of salty popcorn.  “When you eat a bucket of popcorn you get very thirsty because salt is the hypertonic solution. The water in your cells wants to come out to take some of the concentration of the salt away because it is too high for your cells.” (this process is known as osmosis)

 How are the processes of exchange, diffusion and osmosis important in other parts of your body?  Gas Exchange Video Gas Exchange Video

 BellRinger ◦ Explain how diffusion is important to gas exchange  Objectives ◦ Design a controlled experiment to test diffusion and osmosis across a selectively permeable membrane  Homework ◦ FINISH RESEARCH PROJECTS!! DUE WED!

 Read “Too Much Water” 1.Describe the main function of the excretory/urinary system 2.Draw and name the main organs of the urinary system 3.Where does urination get its name from? 4.What is a diuretic and how can it upset the body’s homeostasis?  What are some stressors that can effect the urinary system?  What happens when homeostasis in the Urinary System is disrupted?  Dialysis video Dialysis video

 Read intro on p. 161  What are you testing in this experiment?  Common substances found in blood ◦ Glucose ◦ Starch  Why these? ◦ Commonly found in the blood ◦ Test for presence with indicators (p. 162)

 Purpose ◦ Why are we conducting this experiment? (refer to p. 161)  Background 1. Explain why someone would have to undergo dialysis (how has their homeostasis been disrupted?) 2. What structure in the body does dialysis tubing imitate and why? 3. What is the difference between glucose and starch and what indicators test for the presence of each? (p.162)  Hypothesis ◦ What qualitative and quantitative changes do you expect to see? Why?

Experimental Design 1. You will have access to 3 solutions: ◦ Distilled water ◦ Starch ◦ Glucose 2. Your group of 3 will decide which solution you are going to put in which environment 3. Tie the tube off at one end before adding any solution 4. Iodine must be added OPPOSITE of the starch 5. DO NOT over fill the tubes, they have to fit into the cup 6. Rinse and dry the tube before weighing 7. Be sure to get initial qualitative and quantitative data

 BellRinger ◦ Get the final data for your group  Objectives ◦ Collect and analyze data from a controlled experiment  Homework ◦ Finish the analysis questions from the membrane handout

 What happened?  How do you know?  What does it mean?  Why?

 Jot down your initial thoughts about how a cell can “select” what it lets in and out

 BellRinger ◦ Compare and contrast the cell membrane and the dialysis membrane.  What features do they share?  What features make them different?  Objectives ◦ Describe how the properties of the cell membrane allow a cell to be selectively permeable ◦ Differentiate between passive and active transport  Homework 1. Describe the structure of the cell membrane 2. Describe the function of the cell membrane 3. Explain how the structure of the membrane allows it to do its function

 Cell membrane is the boundary between inside & outside… ◦ separates cell from its environment IN food carbohydrates sugars, proteins amino acids lipids salts, O 2, H 2 O OUT waste ammonia salts CO 2 H2OH2O products cell needs materials in & products or waste out IN OUT Can it be an impenetrable boundary? NO!

 Use the image on pg. 221 in your text and the directions on the handout to construct a model of the plasma membrane.  Be sure to play close attention to the following structures ◦ Lipid bilayer ◦ Membrane protein ◦ Carbohydrate

Plasma Membrane  Barrier for cell contents  Double phospholipid layer ◦ Hydrophilic “water loving” heads ◦ Hydrophobic “water fearing” tails  Also contains proteins, cholesterol, and glycoproteins

 Hydrophilic head, hydrophobic tail  How does this relate to the arrangement of the membrane?

 The phospholipid is a POLAR molecule  Polarity = An unbalanced charge over a single molecule  Two molecules that are both polar? ◦ Repel? ◦ Attract?

 Due to the polar structure, the membrane is only permeable to certain molecules  Which ones may pass, and which may not? Why?

 What molecules can get through directly? ◦ fats & other lipids ◦ Small, Non-polar molecules inside cell outside cell lipid salt aa H2OH2O sugar NH 3  What molecules can NOT get through directly?  polar molecules H2OH2O  ions  salts, ammonia  large molecules  starches, proteins  How do these molecules get into the cell?

 Membrane becomes semi-permeable with protein channels ◦ specific channels allow specific material across cell membrane inside cell outside cell sugaraa H2OH2O salt NH 3

 BellRinger ◦ Review the structure and function of the membrane with a partner  Objectives ◦ Describe how the properties of the cell membrane allow a cell to be selectively permeable ◦ Differentiate between passive and active transport  Homework ◦ Complete AQ 1-6 pgs (do this on loose leaf)

 Membrane transport—movement of substances into and out of the cell  Two basic methods of transport 1.Passive transport  No energy is required 2.Active transport  Cell must provide metabolic energy (ATP)  Video Video

 What if a cell has a lot of a substance, like sodium, but it needs more?  Active transport  diffusion against concentration gradient low  high  uses a pump  requires ATP (energy)

 What is the difference between active and passive transport?  When would a cell need to perform active transport?

 Read the continuation of Josh’s story-p.167  Examine the data at the bottom of p.167 and answer the analysis questions on p ◦ This will be turned in