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.222-224 Diffusion Video

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 2nd law of thermodynamics

diffusion osmosis

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

hypotonic hypertonic

water

net movement of water

freshwater balanced saltwater

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

HomeworkRead the essay “Making Exchanges..” p. 224-225Write 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

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 system2. Draw and name the main organs of

the urinary system3. 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

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)

Background1. 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

Homework1. Describe the structure of the cell membrane2. Describe the function of the cell membrane3. 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

INfoodcarbohydratessugars, proteinsamino acidslipidssalts, O2, H2O

OUTwasteammoniasaltsCO2

H2O 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

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 H2Osugar

NH3

What molecules can NOT get through directly?

polar molecules

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

sugaraaH2O

saltNH3

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 168-169 (do this on loose

leaf)

Membrane transport—movement of substances into and out of the cell

Two basic methods of transport1. Passive transport

No energy is required2. Active transport

Cell must provide metabolic energy (ATP)

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. 168-169◦ This will be turned in