As the activity uses chocolate candies, identify students
with this food allergy. Another colored candy may be substituted,
and students do not need to eat the candy in order to understand
the lesson. Do not conduct this demo in the laboratory, but
rather move to an open classroom, hallway, or courtyard. You
need a space only about 5m X 5m.
3 plastic bowls
1 plastic funnel (big enough for M&Ms to pass through)
4 small jars with lids (baby food jars)
~100 green M&Ms
~100 blue M&Ms
~100 yellow M&Ms
3-4 plastic cups
Estimated Time: 1 hour 30 minutes
Maximum Cost: $25
Before you start
Pour blue M&Ms into one of the bowls.
Pour green M&Ms into another one of the bowls.
Fill two jars half-way with yellow M&Ms.
1. Facilitate student review of neurotransmission. (Hit these
highlights: Synthetic enzymes for neurotransmitters are made
in the cell body, transported to the axon terminal via microtubules,
and react with chemical precursors to make neurotransmitters.
When an action potential arrives at the terminal, neurotransmitters
are released and bind to postsynaptic receptors. Degradative
enzymes break down neurotransmitters in the synapse.)
Recruit volunteers for the following roles. (Students can
make necklace cards or hats with these abbreviations to remind
them of their roles.)
Body (CB): Holds blue M&Ms (synthetic enzymes)
(M): Transports blue M&Ms (can be more than one)
Terminal (A): Holds yellow M&Ms (precursors)
Releases green M&Ms (serotonin)
(R): Receives green M&Ms (serotonin)
Potential (AP): Triggers green M&M release
Enzyme (Z): Destroys green M&Ms (serotonin)
(E, for ecstasy): Gives green M&Ms (serotonin) in mass
quantities to R.
Facilitate student review of specific duties. (Make diagrams,
note cards, or additions to their necklace cards. See Fig.
4. Places please: Ask volunteers to stand in their places,
according to Fig 4. (We have enjoyed placing stage directions
on colorful cut-outs on the floor.)
Ask other student aides to place props.
a. Place the bowl of blue M&Ms in front of the cell body
b. Give two empty jars to the microtubule student(s) (M).
c. Place the bowl with the green M&Ms and the jars with
yellow M&Ms in front of the terminal (A).
d. Place an empty bowl in the hands of degradative enzyme
(Z) and ask the receptor (R) to hold the funnel over the bowl.
Normal (Drug-Free) Neurotransmission
a. The blue M&Ms in the bowl, held by Student CB, represent
the enzymes made by the cell body. The yellow M&Ms in
the jars held by Student A, represent the precursors present
in the axon terminal.
b. Students M (microtubules) carry enzymes to the axon terminal
(Student A) in a jar filled halfway with blue M&Ms (synthetic
c. Student M will then pour the blue M&Ms into the jar
with yellow M&Ms (precursors).
d. Explain to the students that as the enzymes (blue M&Ms)
react with the precursors (yellow M&Ms), the neurotransmitters
(green M&Ms) are synthesized. (Just as mixing the colors
blue and yellow makes the color green.) Shake the jar with
blue and yellow M&Ms to represent synthesis, then place
the jar into the bowl with green M&M. Use green M&Ms
from here on; serotonin is ready.
e. For a neuron to communicate, an action potential travels
from the cell body to axon terminal and signals neurotransmitter
release. Student AP (action potential) walks from the cell
body (Student CB) to the axon terminal (Student A) and tap
Student A on the shoulder. Student A (axon terminal) then
takes some green M&Ms and pours them through the funnel
held by Student R (receptor). This funnel represents a binding
site. The neurotransmitters (green M&Ms) fall through
the funnel into a bowl, held by Student Z (degradative enzyme).
f. The degradative enzyme (Student Z) takes the neurotransmitters
(green M&Ms) from the bowl and degrades them by eating
them (!) or giving them to other students to degrade (eat!).
(Alternatively the M&Ms can be placed in a trash receptacle
to represent inactivation.)
g. Repeat as often as you like.
a. Plan to repeat the sequence again, but this time ask MDMA
(Student E) to grab handfuls of green M&Ms (serotonin)
from the bowl in front of the axon terminal (Student A) and
dump them into the degradation site.
b. Once the bowl with the serotonin (green M&Ms) is empty,
the axon is destroyed; Student A sits down. Once Student A
sits down, Student(s) M also sit(s) down. These events represent
the degradation of the serotonin axon terminal and axon.
c. Ask students whether or not neurotransmission can occur
when the axon terminal and axons are destroyed. (The answer