bellringer ◦ review the definitions for the following terms from the “molecular movement”...
TRANSCRIPT
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
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
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
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
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?