Teachable Unit: Group I Biochemistry
Authors: Mawadda Al-Naeeli, Pat Cipriano, Kim Conner, Lopa Das,
Thea Edwards, Tara Luke
Facilitators: Michelle Withers & Karen York
Title: Cell Membrane Structure and Function
Learning Objective:
To understand how the chemical structure of the
eukaryotic cell membrane underlies its function and adaptability, students will be
able to
 Name structural components of membranes and explain their individual
roles in membranes.
 Describe how structural components fit together to form a membrane.
 Predict emergent properties of membranes
 Describe how membranes change in response to environmental conditions.
 Predict membrane structure and function in extreme environments and
under disease conditions.
Outline
Students will have read the assigned material before class, and taken a pre-class
quiz on the material.
1. Identify primary membrane functions and membrane components.
Activity: Students are asked to list these at home.
They will identify that the membrane is a phospholipid bilayer with
embedded mobile proteins, carbohydrates and fats, such as
cholesterol.
2. Describe arrangement of primary membrane components, including
constraints to membrane structure (what is fixed, what is flexible about
structure?)
Activity: Students are asked to draw and label a membrane model,
showing the phospholipid bilayer with embedded proteins, etc.
3. Identify roles of each primary component in membrane function
Activity: Students are asked to predict effects of under- or overabundance of various components on cell or membrane function. This
activity could be attached to diseases or dietary habits.
Teachable Tidbit
4. Discover membranes as fluid/dynamic structures.
At the end of this tidbit, students will be able to
• predict how fluidity is determined by lipid components of the
membrane,
• predict how the lipid composition changes to maintain fluidity in
extreme environments (tropical versus arctic),
• practice drawing, reading, and interpreting graphs,
• apply the concept of fluidity of a cell membrane to disease.
Sequence of activities:
Hook: Use the claims of positive health benefits of Omega-3
fatty acids to introduce the topic of membrane lipids.
Discuss the fluid nature of membranes with an example of an
experiment that helped elucidate this (video of how a cell
recovers from photo-bleaching fluorescently tagged proteins
embedded in its plasma membrane).
Describe some of the factors that contribute to rigidity/fluidity
within membranes, including type of fatty acid
(unsaturated/saturated) and additional molecules (such as
cholesterol).
Clicker question concerning temperature and membrane
fluidity.
Activity concerning cholesterol and unsaturated and saturated
fatty acids in cell membranes and their relationship to
temperature.
Activity involving the graphing of the “data” that were
developed from the previous activity. This will allow students
to demonstrate understanding of the scientific principles being
discussed, while providing practice and experience with
constructing a graph as a means of presenting data.
Compare hypothetical dataset developed in the previous
activity to published graph that illustrates cholesterol content
in copepods found at different temperatures to reinforce the
trend, and provide additional practice in interpreting a graph.
Administer a summative assessment question involving
subsets of variables. Students will be able to demonstrate their
understanding of the effects of both temperature and lipid
content on the fluidity of cell membranes. This question has
multiple variables that can be substituted to adapt it to in-class
discussions, homework, and exams.
Tie this material back to human health by giving an example of
human pathology associated with disease or dietary choices
that cause changes in cell membranes.
Assessment:
Both formative and summative assessments are addressed in
this unit. Formative assessment is in the form of clicker questions and
teamwork that demonstrate knowledge or misconceptions about each
individual component. Summative assessment is in the form of multipart adaptable questions that can be administered to groups in class,
and included in a different form on a written exam.