Eukaryotic Cell Organization:
Breaking the Jell-O Salad
Mold
Stephanie Aamodt, LSU-Shreveport
Beverly Clendening, Hofstra Univ.
Hans Landel, Edmonds Community College
Doug Luckie, MSU
John Rebers, Northern Michigan University
Description of the Challenge
Our group: Cell/Developmental Biology
Target: introductory biology course, majors or nonmajors, of any size
The Misunderstanding: the eukaryotic cell is a collection
of individual and isolated parts, randomly arranged in the
cell
The “Jell-O Salad” paradigm
You will see later what we want students to think instead
the “Jell-O Salad” model (what our objectives are) because
we do not want to prejudice you, but we can tell you:
Emphasis on model-based reasoning, relying on analogy
Specific objectives are in our course description document
Learning Goals/Objectives
After completing this unit the student will:
 Be able to describe cellular organization and the way this
organization relates to function
 Be able to relate the organization of the cell to different
functional activities
 Be able to make reasonable assumptions about the reasons for
differences between prokaryotic and eukaryotic cells
At the end of the course, the student will:
• Be able to apply the idea that function is dependent on
organized structure to the organization of living things,
including the following levels:




o
o
o
o
Chemical/molecular
Cellular/organelle
Tissue/organ/system
Organisms/ecosystems
Preliminaries
Before this class
Preliminary introduction to macromolecules
Class discussion: Define “living things” and generate
list of requirements
Introduce cells as the “smallest unit of life”
All cells have membrane, DNA, cytoplasm
“The class part”
Run through first part of class
Summary
Car is organized
parts
subsystems
systems
connections
Organization is important to function
Car has processes
simultaneous
connections
Processes important to function
Processes and Organization are interdependent
“The FIRST part”
Describe rest of class
TRANSITION: Bring the Class to
Biology
have been examining a non-living object
let’s use what we have learned about the car to
examine a living object -- the human body
TRANSITION: Bring the Class to
Biology
The procedures with the car has served as a model for what
we would like the students to do.
Car will serve as an analogy
Now use the same procedure as with the car, but with the
human body
list functions body must perform to live
list body parts
categorize body parts according to function
parts must be assembled in correct locations
certain activities must occur for body to function
may or may not include formative assessment by performing
“perturb and predict” exercises
Concept Maps
NOTE: Homework (assessment) will include
concept mapping of cell parts with respect to
function
If students have not been introduced to concept
maps, a good place to introduce them is at the
point when they are asked to categorize the parts
of the body according to function. This will
model for them what we would like them to do in
the homework assignment.
Possible example concept map: plants
Example of a poor concept map
“Sentence-in-a-box”
Poor concept map
Good concept map
should show complex
relationships
One part can have
multiple relationships
Use linking terms to
show how parts are
related
Focus on most
important connections
FOCUS: Bring the class to
the cell level
Important transition
Have established a context for
describing and understanding the cell
Break the “Jell-O salad mold”
More than a boring parts list
Structures are not isolated; they are
interconnected
Structures are not randomly placed; they are
highly organized
The organization is not static; it is dynamic
Repeat steps 1 through 3
Ask the class to list functions cell must
perform to live, and the parts of the cell
Can the students group the parts according
to function?
Can the students organize the parts of the
cell? Make connections?
Recognize that student
knowledge is limited
Students will have some prior knowledge,
but it will be simple, pat definitions.
Allow class to explicitly identify what they
don’t know or understand.
Emphasize that what we don’t know as a
class will direct the rest of the unit.
Model a dynamic view of the cell
Present an exciting mini-lecture on one cell
structure or organelle as an example for the class.
Include a video clip of a cell process such as
mitosis or transport or a cell in motion.
Describe how the structure is made of smaller
parts that fit together precisely to allow a specific,
controlled process
(Here, “model” means showing students what we
expect them to do)
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Encourage students to think
The contextual framework will be
reinforced by homework and assessments.
The dynamic, highly organized view of life
will be further developed in classes on
cellular respiration, mitosis and most other
topics, as well, as the course continues into
the study of cell biology.
Assignment
1. Complete the structure/function chart for the cell
that was begun in class. The information can be
found in Chapter x of your textbook.
• this forces the students to learn the parts on their
own, but within the context of function
2. Draw a concept map that shows the spatial and
functional relationships among
nucleus
endoplasmic reticulum
ribosomes
mitochondria
cytosol
synthesis of macromolecules (anabolic metabolism)
breakdown of macromolecules for energy production
(catabolic metabolism)
Examples of connecting phrases (is connected to, takes
place in , etc.)
this assesses their understanding of the concepts of
spatial and temporal organization
3. Label the cell compartments with their functions.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
4. Predict, in detail, what would happen if
Group A
• there was a hole in the cell membrane.
• the cell had no mitochondria.
• a mature cell lost its nucleus.
Group B
• none of the ribosomes were attached to the endoplasmic
reticulum.
• the process of vesicle formation could not occur (the Golgi
apparatus could not form vesicles).
Pick one from Group A and one from Group B
this assesses their understanding of the importance
of spatial and temporal organization of cells
The EXCITING significance of
this unit
It covers a BIG idea in Biology
It is “scalable” for use in other topics
The Big Idea
Living Things Are Organized.
Spatially- certain parts are located in certain
places
Temporally - certain processes take place in a
certain order
Function is dependent on both spatial and
temporal organization
Interconnected
Interactions
Hierarchical (systems, subsystems, subsubsystems . . .)
Permeation of the “Big Idea”
you can (and we think you should) re-examine the
importance of spatial and temporal organization
when the following cellular topics are discussed
Metabolism
Mitosis
Protein synthesis
Intracellular signaling
Intercellular signaling
our assessments can be used after any of these
topics, and in midterm and final exams
“Active Transport” of the “Big Idea”
The Big Idea applies (by definition) to all levels of
biology. We think it should be continually
stressed.
•
•
•
•
•
•
•
Macromolecules
Organelles
Tissues
Organs
Organisms
Communities
Ecosystems
Scalability of Exercise
Because life is hierarchically organized,
with each level exhibiting spatial and
temporal organization (i.e., because it is a
Big Idea), this exercise can be used at any
level.
(it has wide applicability)
Living things are organized.
Replace “Living Things” with . . .
•
•
•
•
•
•
•
Macromolecules
Organelles
Tissues
Organs
Organisms
Communities
Ecosystems
Revisions?
Feedback from FIRST participants suggests
Transition (human body) step can be left out
Car analogy has sexual bias -- women will
have a harder time relating to it
• we had discussed this and had decided to address
this by calling on women first
• also, you can use ANY object you would like as
your analogy, as long as it it sufficiently complex,
has processes, and is understandable by the
majority of your students (see course description
document)