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.
Do Now: (in your notebook) Which molecule is bigger, starch or glucose?
Explain with a diagram in our notebook. Today’s Objectives:
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.
Bio 9C: Thursday, 12.2.10Title: Movement Across Cell Membranes – Day 1
MOVEMENT ACROSS CELL MEMBRANESMoretti and Dickson
Planning the Experiment: Individual:
Read Overview Small Groups:
Planning the Experiment How do we test for Starch
and Glucose? Whole Class Discussion
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
Class Discussion: 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.
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
Demo What is happening to the dye in the water? Based on prior knowledge, what do you think
this is called?
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)
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
New Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Diffusion
Osmosis
Selective Permeability When a cell membrane (or
any membrane for that matter) only allows certain materials to pass across the membrane and not others
Substance usually pass across based on the size, shape, and charge (+/-/neutral) of the molecules
New Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Diffusion, Osmosis and Selective Permeability In Action:
http://zoology.okstate.edu/zoo_lrc/biol1114/tutorials/Flash/Osmosis_Animation.htm
New Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Homework:Type the following sections of the Diffusion Lab:
Background Info Purpose/Hypothesis Summary of Procedure
Do Now: (in your notebook) Take out lab prep and get ready to review
procedures Today’s Objectives:
Design an experiment to test diffusion of starch and glucose across a membrane
Use scientific vocabulary to explain how a cell membrane controls what enters and leaves a cell
Bio 9C: Friday, 12.3.10Title: Movement Across Cell Membranes – Day 2
Review Experimental Set-Up: 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-ish
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
Review Experimental Set-Up: Part III:
How do you know the following substances have left the bag: Starch? Glucose?
What other substances might move across the bag? How will you know?
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 and Iodine
Starch & Glucose Solution
Review Experimental Set-Up: Part I:
Preparing Dialysis Bag Soak the dialysis tube in water to soften Tie one end into a knot Fill the tube about half-way w/ starch/ glucose solution Tie the other end of the tube into a knot to seal the bag Rinse w/ tap water to wash excess solution from outside of bag
Preparing the Beaker Label your beaker Fill a 140 ml beaker ¾ of the way with water Add 10-15 drops of Iodine to water and mix . Note the color of the water Test water with glucose test strip and note any color change
Preparing the Model: Put dialysis bag into beaker with water and iodine solution
Part II: Wait 30 min to allow for substances to move across the membrane
Part III: Data Collection
Diagram the experimental set-up Create a data table to collect data Collect data by recording any color change to
the beaker, dialysis bag, and/or glucose test strip.
Implementing the Lab:Diffusion Across Cell Membranes
Water and Iodine
Starch & Glucose Solution
Lipid Bilayer Two layers of lipids that form
the outer membrane of a cell. Flexible Strong Do not Dissolve in water
New 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
Homework:Finish Typing the Following Section of the Lab:
Data/ Results Analysis Conclusion
Bring in a printed copy of your background information section to class on Monday!!!
Do Now: What is the purpose of the lab?
Today’s Objectives: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell Make clear connections between various vocabulary words and concepts
to each other and to the purpose of the lab, so as to write a better Background Information Section.
Bio 9C: Monday, 12.6.10Title: Movement Across Cell Membranes – Day 3
Facilitated Diffusion When a substance diffuses
through a membrane by going through a protein channel
Regular diffusion goes through the lipid bilayer
New Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Prote
in Ch
anne
l
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!
New Vocabulary
Objectives for Class: Use scientific vocabulary to explain how a cell membrane controls what
enters and leaves a cell
Diffusion Across Cell Membranes:Review Background Information
Objectives for Class:• Implement an experiment to test diffusion of starch and glucose across a
membrane
Background Information Brainstorm•
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
Work in your groups to explain what your results mean. If there are color changes, state
was this means in terms of what substances are present, but
DO NOT explain why the substance is where it is (this should go in the conclusion section)
Water and Iodine
Starch & Glucose Solution
Objectives for Class:• Use scientific vocabulary to explain how a cell membrane controls what enters and
leaves a cell• Make clear connections between various vocabulary words and concepts to each other
and to the purpose of the lab, so as to write a better Background Information Section.
Diffusion Across Cell Membranes:Data Analysis
Homework:Finish Typing/ Revising the Lab Report:
Final Copy Due Thursday w/ Rubric! Do Now:
Take out the Typed Background Information Section of the Denatured Enzymes Lab Report
Today’s Objectives: Use scientific vocabulary to explain how a cell membrane
controls what enters and leaves a cell Make clear connections between various vocabulary words
and concepts to each other and to the purpose of the lab, so as to write a better Background Information Section.
Bio 9C: Tuesday, 12.7.10Title: Movement Across Cell Membranes – Day 4
Objectives for Class:• Use scientific vocabulary to explain how a cell membrane controls what enters and
leaves a cell• Make clear connections between various vocabulary words and concepts to each other
and to the purpose of the lab, so as to write a better Background Information Section.
Writing Better Background Information Sections
Task I: Read the to example Background Information
sections from the Denatured Enzyme Lab and grade them according to the rubric.
Discuss the grading
Objectives for Class:• Use scientific vocabulary to explain how a cell membrane controls what enters and
leaves a cell• Make clear connections between various vocabulary words and concepts to each
other and to the purpose of the lab, so as to write a better Background Information Section.
Writing Better Background Information Sections
Task II: Whole Class Create a mind-map to connect
the vocabulary and concepts for the Background Information Section. This will help us outline this section for us as well.
Objectives for Class:• Use scientific vocabulary to explain how a cell membrane controls what enters and
leaves a cell• Make clear connections between various vocabulary words and concepts to each other
and to the purpose of the lab, so as to write a better Background Information Section.
Writing Better Background Information Sections
Task III: Use mind-map/
outline to re-write your background information section more effectively.
Revise Background Information Section
Complete all sections of the Lab Report
Water and Iodine
Starch & Glucose Solution
Objectives for Class:• Use scientific vocabulary to explain how a cell membrane controls what enters and
leaves a cell• Make clear connections between various vocabulary words and concepts to each other
and to the purpose of the lab, so as to write a better Background Information Section.
Diffusion Across Cell Membranes:Complete Lab Report
Homework: Do Now: Today’s Objectives:
Bio 9C: Wednesday, 12.8.10Title: No Class – Half Day