movement across cell membranes
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Movement Across cell Membranes. Moretti and Dickson. Bio 9D: Thursday, 12.2.10 Title: Movement Across Cell Membranes – Day 1. Homework: Read pages 182-189 (Section 7-3): Take notes based on the questions on the back of Assignment Sheet and write your answers in your notebook. - PowerPoint PPT PresentationTRANSCRIPT
Homework:Read pages 182-189 (Section 7-3): Take notes based on the questions on the back of Assignment Sheet and write your answers in your notebook.
Silent Do Now: (in your notebook w/ title & date)1. Which molecule is bigger, starch or
glucose? Explain with a diagram in your notebook.
2. Do you want to share a slide or paragraph from your digestion story with the class? If so, write down exactly which slide or paragraph you would like to share.
3. Take out the project rubric and the project if it’s printed.
Bio 9D: Thursday, 12.2.10Title: Movement Across Cell Membranes – Day 1
Today’s Agenda & Objectives
Update on Class Contract: We are still going strong to get Round 2 of
cookies on Monday One strike earned on Tuesday No strikes earned yesterday No Class Contract violations
Let’s make today great so we can stay on track!
Objective: Moving on to a new unit SWBAT design an experiment to test which
molecules can pass through a cell membrane (drawing on knowledge of glucose, starch, and chemical indicators)
Today’s Agenda & Objectives
Objective: Moving on to a new unit SWBAT design an experiment to test
which molecules can pass through a cell membrane (drawing on knowledge of glucose, starch, and chemical indicators)
Agenda: Quick sharing of Digestion Projects (10
min max) Review Do Now (5 min max) Experiment Design (30 min)
Planning the Experiment: Individual:
Read Overview Small Groups:
Planning the Experiment How do we test for Starch and
Glucose?
Whole Class Discussion Small Group:
Experimental Set-Up Whole Class Review:
Experimental Set-Up
Designing a Lab:Diffusion Across Cell Membranes
Objectives for Class: Design an experiment by drawing from your knowledge of starch,
glucose, cell membranes, and experimental indicators that test for the presence of starch and glucose.
Water
Model Cell w/ Dialysis Tubing Membrane
Starch & Glucose Solution
No Homework!
Silent Do Now (in NB w/ title & date) What is happening to the dye in the water? What vocabulary word from last night’s reading
applies to this situation? Why? What do you think will happen to the dye by the
end of class?
Bio 9D: Friday, 12.3.10Title: Movement Across Cell Membranes – Day 2
Check-In from Yesterday
We didn’t get to a contract violation, BUT… It was clear that someone was saying
inappropriate things (maybe more than one person?)
This gets in the way of our progress towards having an excellent class
On the small piece of paper, write: The inappropriate things that were said in class
yesterday Which person or people said them Any other thoughts you have about this.Everyone must write something down.
Today’s Objectives & Agenda
Describe and explain the following terms: Lipid Bilayer Selective Permeability Concentration Diffusion
Use this vocabulary to: Explain how a cell membrane controls what enters and leaves
a cell Design an experiment to test whether glucose and/or starch
can pass through the cell membrane
Agenda: Notes/Discussion/Quick Animation Cell Membrane Experiment:
Purpose & Hypothesis (discuss as class) Set up – Demo, then do it in your group Summarize procedure & make data table Collect data
Lipid Bilayer Two layers of lipids that form
the outer membrane of a cell. Flexible Strong Do not Dissolve in water
Cell Membrane Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Image to the right shows the lipid bilayer of a cell. Notice how it has other components like protein channels & “pumps” built into it.
zoom out
Selective Permeability When a membrane only
allows certain substances to pass across the membrane (and not others)
Substances usually pass across based on the size, shape, and charge (+/-/neutral) of the molecules
Cell Membrane Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Concentration How much “stuff” is in a given
amount of liquid Mass of a solute (stuff in the
liquid) per a given volume of the total solution
i.e.: 12g of salt in 3L of water = 12g/3L = 4g/L
Diffusion Movement of molecules from a
high concentration (more stuff) to low concentration (less stuff)
Cell Membrane Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Diffusion
Osmosis
Diffusion, Osmosis and Selective Permeability In Action:
http://zoology.okstate.edu/zoo_lrc/biol1114/tutorials/Flash/Osmosis_Animation.htm
Cell Membrane Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Purpose of the Experiment:
To figure out whether the cell membrane will allow glucose, starch, or both to pass through the membrane?
Hypothesis: (write your prediction on the lab handout)
Designing a Lab:Diffusion Across Cell Membranes
Objectives for Class: Design an experiment by drawing from your knowledge of starch,
glucose, cell membranes, and experimental indicators that test for the presence of starch and glucose.
Review Experiment Set-Up: Starch
How do we test for it? Use Iodine
How do we know starch has passed through membrane? Iodine outside the dialysis bag turns from yellow-orange to purplish-
brown
Glucose How do we test for it?
Boil it in Benedicts solution or use a glucose test strip How do we know glucose has passed through the membrane?
Glucose test strip will change color
Designing a Lab:Diffusion Across Cell Membranes
Objectives for Class: Design an experiment by drawing from your knowledge of starch,
glucose, cell membranes, and experimental indicators that test for the presence of starch and glucose.
Procedure Overview: Part I:
Set-up Dialysis Bag Moisten tube and tie one end Add the starch & glucose solution to the tube Tie the top of the tube
Rinse w/ tap water to wash excess solution from outside of bag
Set-up Beaker Fill a 250 ml beaker ¾ of the way with water Add Iodine to water – mixture should be orange
Put dialysis bag into beaker with water and iodine Part II: Wait 30 min to allow for substances to
move across the membrane
Designing a Lab:Diffusion Across Cell Membranes
Water and Iodine
Objectives for Class: Design an experiment by drawing from your knowledge of starch,
glucose, cell membranes, and experimental indicators that test for the presence of starch and glucose.
Starch & Glucose Solution
Owen
TraeMiguel Rayoni
Loveng
Nick
Davnys
Samantha
Joas Dyani
Hannah
Courtney
CarlhebDevon
Marcelo
Nekeyla
Christine
Lorreno
Kayla
Jackson
Homework: Type up all sections of lab report except for Background Information
Silent Do Now (in notebook w/ title & date) Take out your Diffusion Lab packet Look at your data table w/ your results Summarize your results in your notebook and try to
explain what each result means. Was there a color change in the beaker? What does this
tell us about a substance that did or did not diffuse? Was there a color change in the bag? What does this tell
us? Was there a color change in the glucose test strip? What
does this tell us?
Bio 9D: Monday, 12.6.10Title: Movement Across Cell Membranes – Day 3
Today’s Objectives & Agenda
Discuss and analyze the results of the diffusion experiment in order to…
Draw conclusions about which substances diffused across the membrane
Agenda: Quick Class Discussion & Revisit the
Animation Typing Time
Color Change?
Diffusion Across Cell Membranes:Presenting the Data/ Results
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Water and Iodine
Starch & Glucose Solution
Bag Turned Purple/ Black
No Color Change to the Water
Glucose Test Strip changed color
Remember:Selective Permeability In Action: http://zoology.okstate.edu/zoo_lrc/biol1114/tutorials/Flash/Osmosis_Animation.htm
Lab Report Typing
Step 1: Set up the Title of your lab report with all required info
Step 2: Set up section headings in order for all sections of your lab report
Step 3: Skip Background Info for now.Step 4: Start typing whichever other section is
easiest for you to start on right now. All sections except Background Info should be typed by tomorrow.
Work quietly, talking with your lab partner only.
No internet use allowed until last 5 minutes of class (for emailing work).
Homework: Write the Background Info section of your lab report
Silent Do Now (not in notebook!)1. Take a napkin and a brownie!
2. For the next round of treats we will raise the expectations even higher! Do you think we should do this by…(answer on index card)
a) Making the standards for class behavior higher (fewer strikes, more anti-strikes for focused behavior required)
b) Making the length of time longer (two weeks without breaking contract)
3. On the handout: Read, evaluate, and write strengths & weaknesses for Example 1 and Example 2
Bio 9D: Tuesday, 12.7.10Title: Movement Across Cell Membranes – Day 3
Today’s Objectives & Agenda
Write an excellent Background Info section of a lab report Use the lab report rubric to identify mediocre
versus excellent examples of Background Info sections
Write explanations and connections for all important terms and concepts for the Diffusion Lab background info
Agenda: Evaluate examples of Background Info Class discussion Organize info for Diffusion Lab Background Info
Sample Background Info sections
Strengths:good knowledge of vocab words; made sure the reader understood the key terms
Things to improve: using the key terms to connect to the lab; more like a list of definitions; opening sentence could be more engaging; take out words like : “here’s what you need to know”
Overall grade:15/20…. C rass
Strengths: They explained things well, they gave examples of chemical equations, they have proper formatting, the diagrams are a good explanation for a bunch of vocab words. They connect the key terms to the lab. more _______
Things to improve: explain monosaccharide and polysaccarides better.
Overall grade: 18 out of 20 8] B]
Example 1 Example 2
Objectives for Class: Use the lab report rubric to identify mediocre versus excellent examples of Background Info sections
Diffusion Lab Background Info You have 7 minutes to complete the
explanations for each term listed, plus at least 2 others
Do this by referring to your notes Work quietly, stay focused on the task,
and be productive!
Connections between words…
Homework: Complete lab report due tomorrow – typed, printed, stapled, ready to hand in w/ rubric @ start of class.
Silent Do Now (in NB w/ title and date)1. Write down what you understand about
diffusion and concentration (check your notes for reminders). What are they and how to they relate to each other?
2. What is an example of diffusion that you have seen in everyday life?
Bio 9D: Wednesday, 12.8.10Title: Cell Membranes Wrap-Up
Today’s Objectives & Agenda
SWBAT… Define and illustrate 4 ways that substances can move
across cell membranes Diffusion, osmosis, facilitated diffusion, and active transport
Explain when each process would be used for materials entering a cell
Agenda: Notes/Discussion on Vocabulary
We are going to hold “tangent” questions until the end today! Review Questions (Worksheet)Remember: Earn treat-points for sustained productive
class.Strikes for side conversations that interrupt class (3 per class starts the treat-cycle over)
Concentration How much “stuff” is in a given amount
of liquid Diffusion
Movement of molecules from a high concentration (more stuff) to low concentration (less stuff)
Osmosis Movement of water through a
selectively permeable membrane from a high concentration to low concentrationNote: For osmosis to occur, the membrane only allows water to pass across and not the solute
Cell Membrane Vocab Review
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Diffusion
Osmosis
Facilitated Diffusion When a substance diffuses
through a membrane by going through a protein channel
Regular diffusion goes through the lipid bilayer
Cell Membrane Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Prot
ein
Cha
nnel
Active Transport When a substance is pumped across a
membrane from where there’s a low concentration (less stuff) to where there’s a high concentration (more stuff)
Requires a pump (made of protein) and ATP energy!
Cell Membrane Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Today’s Objectives & Agenda
SWBAT… Define and illustrate diffusion, osmosis, facilitated
diffusion, and active transport Explain when each process would be used for
materials entering a cell
Agenda: Notes/Discussion: Facilitated Diffusion & Active
Transport Review Questions
Work on your own Finish in class, otherwise for HW along w/ lab
report