Selective Permeability-Modeling Cell Membranes
Name_________________________
Date__________
Period____
Standard(s):
1.a.
Students know cells are enclosed within semipermeable membranes that regulate
their interaction with their surroundings
Objectives: SWBAT…
 Explain the concept of selective permeability as a form of passive transport
 Connect selective permeability in cells to the selectively permeable model created
using the balloon.
Introduction: You will be given an opportunity to examine a balloon with a scent in it.
You will be able to smell the scent through the balloon. How is this possible?
Directions: Examine the balloon and create a model to explain why you are able to
smell the scent inside of the balloon. Use the following terms in your explanation:
diffusion, selective permeability, concentration gradient, balloon, and scented
“molecules”. You may create this model by using SMARTBoard software, copying and
pasting images from the internet, or using another computer programs.
Resources:
 http://www.tvdsb.on.ca/WESTMIN/science/sbi3a1/cells/Osmosis.htm
 http://www.youtube.com/watch?NR=1&v=AYNwynwaALo
 http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion
_works.html
 http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_
works.html
Model:
Explanation: (diffusion, selective permeability, concentration gradient,
balloon, and scented “molecules”).
Follow-up Questions: Answer the questions below in complete sentences.
1.) What does the term selective permeability mean?
2.) How is the cell membrane similar to the balloon?
3.) Why is it possible to smell the scent if it is inside of the balloon?
4.) Explain what a concentration gradient is and what it means for the scented
molecules to diffuse down their concentration gradient.