Cell Transport across the cell membrane
Kathy Jardine and Brian Evans
July 17, 2014
INFORM ATION ABOUT THE LESSON
Grade Level and Subject Area
10 (9-11): Biology
Time Frame
4-45 min class periods
Objectives: Upon completion of this unit, students will be able to:
•
•
•
•
•
•
•
•
To understand the engineering design cycle
Identify the different parts of a phospholipid bilayer
Define osmosis, diffusion, active transport
Model a semi-permeable membrane
Define/identify examples of diffusion
Differentiate between passive and active transport including examples of each
Design and build a semi-functional model of the phospholipid bilayer
Model how a concentration gradient influences the transport of materials across a membrane
Next Generation Science Standards
HS-LS1 From Molecules to Organisms: Structures and Processes
HSAnalyze a major global challenge to specify qualitative and quantitative criteria and constraints for solutions that
ETS1-1. account for societal needs and wants.
HSDesign a solution to a complex real-world problem by breaking it down into smaller, more manageable problems
ETS1-2. that can be solved through engineering.
Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a
HSrange of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and
ETS1-3.
environmental impacts.
Standards for Technological Literacy
RST.11- Integrate and evaluate multiple sources of information presented in diverse formats and media (e.g., quantitative
12.7
data, video, multimedia) in order to address a question or solve a problem. (HS-ETS1-1),(HS-ETS1-3)
Evaluate the hypotheses, data, analysis, and conclusions in a science or technical text, verifying the data when
RST.11possible and corroborating or challenging conclusions with other sources of information. (HS-ETS1-1),(HS12.8
ETS1-3)
RST.11- Synthesize information from a range of sources (e.g., texts, experiments, simulations) into a coherent
12.9
understanding of a process, phenomenon, or concept, resolving conflicting information when possible. (HSETS1-1),(HS-ETS1-3)
Common Core State Standards in M athematics
M P.2 Reason abstractly and quantitatively. (HS-ETS1-1),(HS-ETS1-3),(HS-ETS1-4)
Common Core State Standards in English and Language Arts
RST.11- Cite specific textual evidence to support analysis of science and technical texts, attending to important distinctions
12.1
the author makes and to any gaps or inconsistencies in the account. (HS-LS1-1)
Write informative/explanatory texts, including the narration of historical events, scientific procedures/ experiments,
WHST.9- or technical processes. (HS-LS1-1)
12.2
WHST.9-12.9 Draw evidence from informational texts to support analysis, reflection, and research. (HS-LS1-1)
Prior Learning
Any previous learning about cellular membranes, cellular transport would be used in this lesson.
M aterials
Your textbook, your own notes, beaker with water, food coloring, computer with internet access, for detailed description of
materials see Appendix A.
Day 1: LESSON IM PLEMENTATION
Objective: Upon completion of this lesson, students will be able to:
To understand the engineering design cycle
Pre-Assessment
Do you know what engineering design cycle? And how it relates to biology?
Procedures
Time:
45 min –
1 class
period
1. Introduce the engineering design cycle and relate it
to the scientific method
2. Discuss the work of biomedical engineers.
3. Give students a list of diseases that are caused by a
malfunctioning plasma membrane.
4. Start to introduce phospholipid bilayer components.
5. Put food coloring in a beaker filled with water:
discuss what is occurring. (diffusion)
6. Show animation from internet if necessary to
visualize the diffusion and osmosis processes.
Formative Assessment
Classroom discussion
Purpose:
introduce
experimental
design
Closure
Reflect:
1.) What did you learn today?
2.) What are some ways that biomedical engineers are useful in the medical field?
3.) How is diffusion different than osmosis?
Summative Assessment
At the end of the hour, have groups of two try and list all of the parts of the experimental design process in their
notebooks. Orally discuss and write this on the board.
Day 2: LESSON IM PLEM ENTATION
Objective: Upon completion of this lesson, students will be able to:
•
•
•
•
•
Identify the different parts of a phospholipid bilayer
Define osmosis, diffusion, active transport
Define semi-permeable membrane
Define/identify examples of diffusion
Define/identify examples of active transport
Pre-Assessment
Fill up a beaker with tap water. Discuss what will happen when food coloring is added to it. Drop food coloring
in the beaker. Observe and discuss.
Procedures
Time
Instructional Strategies/Learning Tasks
45min1 class
period
1. Review topics started on day1
2. Review phospholipid bilayer concepts
3. Teach diffusion and active transport using analogies
and pictures.
4. Show animations from websites if additional resources
are needed.
Purpose:
introduction to
cellular
membranes and
their components
Formative Assessment
THINK-PAIR-SHARE: (Have students answer questions about classroom
discussion):
1. Differentiate between diffusion and facilitated diffusion. Give examples of
molecules that experience each process.
2. Define active transport and give an example of a cell or organism that experiences
this.
3. Discuss how diffusion and active transport are different- (may use a Venn
diagram). W hy is it necessary for a cell or organism to have both?
Closure
Discuss the THINK-PAIR-SHARE; go over any misconceptions.
Summative Assessment
Discuss the THINK-PAIR-SHARE; go over any misconceptions.
Day 3-4: LESSON IM PLEM ENTATION
Objective: Upon completion of this lesson, students will be able to:
Design and build a semi-functional model of the phospholipid bilayer.
Pre-Assessment
What are all of the components of a phospholipid bilayer? Have a student write them on the board; add to this
list if necessary.
Procedures
Time:
45 min –
2 class
periods
1. Give all students a list of materials and what they
need to accomplish.
2. They should write down all of their ideas (5 min).
3. In groups they should compare ideas and pick the
one they think is best (or combine them).
4. In their groups, students should build their model of
the cell membrane. They will need to include
definitions as well as labels of each of the following
(see Appendix B- analysis questions)
5. Their model will have to allow specific molecules to
go through it (items that will represent water,
carbon dioxide, oxygen, glucose, sodium, etc.)
6. W hen they are completed, these will be tested to see
if they work. It will be tested against a rubric
(Appendix A)
Purpose: build a
functional cell
membrane
Formative Assessment
Testing their product for functionality
Closure
Have a class discuss on what everyone has learned. Review any questions still remaining. Prepare for a quiz.
Summative Assessment
Quiz time!
Some ideas and parts of this lesson plan were inspired by the lesson “Keepers of the Gate”
from the website:
http://www.teachengineering.org/ on July 18, 2014
Appendix A- Engineering Design Project Handout
Scenario:
The plasma membrane plays an integral role in maintaining homeostasis by controlling what comes into and out of the
cell. We have discussed how small defects that result in some loss of function of the plasma membrane can result in
major disorders, such as Duchenne Muscular Dystrophy.
Some small, non-polar molecules are able to cross the plasma membrane along the concentration gradient directly
through the phospholipid bilayer. Other smaller charged molecules, like water and charged ions, are able to cross the
membrane via channel proteins through the process of facilitated diffusion. Some substrates need to be pumped
across the membrane against the concentration gradient (or may be too large to cross the membrane) and require an
energy input and/or the help of carrier proteins to cross the membrane via active transport.
In this design contest, you will be responsible for designing a 3-D model of a plasma membrane that must allow
different substrates to cross it via a variety of “transport proteins.”
Your model should demonstrate the phospholipid bilayer and incorporate channel proteins and carrier proteins that
will be able to transmit four materials that represent different types of substrates that would need to enter/exit a
cell.
Here are the substances that will need to cross your model membrane, the type of cell transport they would
require, and what will be representing each:
O2/CO2 – simple diffusion – represented by sand
Water and ions –facilitated diffusion via channel proteins – represented by water
Glucose (moving against the gradient (ex)intestine)) – active transport via specialized transmembrane proteins –
represented by a pom pom
Mineral ions(moving against the gradient(ex) in plant roots))- active transport via specialized transmembrane proteins
Materials:
Styrofoam ball - $5.00
Tape (6”) - $ 3.00
Cotton balls (x5) -$3.00
Toothpicks (x10) - $ 2.00
Drinking Straw - $1.00
Coffee Stirrers (x5) – $2.00
Rubber Band – $3.00
Paper Clips (x 10) - $2.00
Craft Foam (2”x2”) - $2.00
String (6”) - $2.00
Cheese cloth (2”x2”) - $1.00
Pipe cleaner – $1.00
Aluminum Foil (2”x2”) - $1.00
Play-doh (1” ball) – $3.00
Q-tips (x25)-$3.00
Science Learning Community: Science and Engineering Lesson
Plans
Grading :
-Structural Accuracy in modeling the membrane and membrane-bound proteins = 30% of Total Design Grade
Points:
15
10
5
0
Requirements:
The model
successfully
demonstrates the
structure of the
phospholipid
bilayer and
transport proteins.
The membrane is a double
layer and phospholipids
are relatively similar to
their actual structure.
Transport proteins are not
embedded in the
membrane and/or carrier
proteins cannot repeatedly
modify their form to attach
with their associated
substrate, pass it through
the membrane, and release
it.
The membrane is a
double layer,
however, the model
does not demonstrate
the structure of the
phospholipids
(phosphate heads
and fatty acid tails).
Transport proteins
are not embedded in
the membrane.
Model in no way
resembles the
structure of a
phospholipid
bilayer. Transport
proteins are not
embedded in the
membrane. It is not
a bilayer.
Amount of material that passed through the membrane (sand = 3 points, water = 4 points, ions large molecules
= 4 points each) = 30% of Total Design Grade (15 points)
Requirements: Sand and water will be massed before and after travelling through the membrane to
determine the percentage of the substrate that was able to successfully cross the membrane. The class
percentages will be divided into thirds. To receive all of the points for sand and/or water the percentage of
sand and/or water that successfully pass through the group’s membrane must fall in the top 3rd of the class.
Water will not be able to cross the membrane without a channel protein. If you do not build a channel
protein, your group will receive a zero for that grade.
Reusability on active transport pumps/carrier proteins = 20% of Total Design Grade
Points:
10
7.5
5
2.5
Requirements:
Carrier proteins can
be reset to their
original position (able
to accept a new
molecule
(marble/pom pom)
within 10 seconds
Carrier proteins can
be reset to their
original position (able
to accept a new
molecule
(marble/pom pom)
within 30 seconds
Carrier proteins can
be reset to their
original position (able
to accept a new
molecule
(marble/pom pom)
within 1 minute
Carrier proteins
cannot be returned
to their original state
after transferring the
molecules through
the membrane
-Money Spent on model supplies (cost) = 20% of Total Design Grade
Points:
Requirements:
10
7.5
5
Total cost of materials
used to build the
model falls is in the
lower 25% of the
class totals.
Total cost of materials
used to build the
model falls is in the
lower 50% of the
class totals.
Total cost of materials
used to build the
model falls is in the
lower 75% of the
class totals.
2.5
Total cost of
materials used to
build the model is
among the most
expensive 25% of
the class totals.
Funded by an Elementary and Secondary Education Act Title IIb Wisconsin Improving Teacher Quality Grant in
Partnership with the University of Wisconsin-Stout
Page 6
Science Learning Community: Science and Engineering Lesson
Plans
Total Design Grade = __________ / 50 points
Appendix B- Analysis questions
Name__________________________________________________Hour_______
__Date______________
Define the following terms in your own words:
1. Cell membrane
2. Phospholipid
a.
Label the hydrophilic (head or tail) and the hydrophobic
head or tail
accordingly
3. Receptor and signal molecules
4. Selective permeability
5. Transport protein channels
6. Cholesterol component
7. Fluid mosaic model
8. Diffusion
a. Example of particles that diffuse through a cell
Funded by an Elementary and Secondary Education Act Title IIb Wisconsin Improving Teacher Quality Grant in
Partnership with the University of Wisconsin-Stout
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Science Learning Community: Science and Engineering Lesson
Plans
9. Active transport
a. Examples of particles that use active transport through a cell
Answer the following questions referring to your model:
1. What part of your model represents the following:
a. Hydrophobic tails?
b. Hydrophilic heads?
c. Transport (carrier) proteins
d. channel proteins
e. cholesterol
2. How is diffusion different from facilitated diffusion? Give an example of a molecule
that does diffusion and one that does facilitated diffusion?
3. Differentiate between active transport and diffusion.
4. Explain how the swabs and straws actually represent the components of a real cell
membrane.
5. Roll the bundle of cotton swabs between your hands. Do the individual swabs move?
Without pulling the straw out can you move it between the swabs? How does this
represent the fluid mosaic model?
Funded by an Elementary and Secondary Education Act Title IIb Wisconsin Improving Teacher Quality Grant in
Partnership with the University of Wisconsin-Stout
Page 8
Science Learning Community: Science and Engineering Lesson
Plans
6. What was the hardest part of building your model?
7. How did completing this project help with your understanding of how a cell
membrane works in a cell?
8. What do you think would happen if one of the components to the cell membrane- say
the transport proteins- all were stuck open? Stuck shut? Be descriptive and scientific in
your answer.
Funded by an Elementary and Secondary Education Act Title IIb Wisconsin Improving Teacher Quality Grant in
Partnership with the University of Wisconsin-Stout
Page 9