4-H Summer Science 2012-Lipids
Lipids and Fish oils
Materials
Overview
-PowerPoint Presentation
Our bodies need energy to function and we get the energy we need
from the food that we eat. Less than a days’ worth or energy comes
from carbohydrates, while the energy we get from eating proteins is
used as we consume it. Fats and oils, known as fatty acids, provide us
with long-term store of energy.
- 2 Molecule Kits: one for each
group
-Handouts of different structures
of molecules. (Provided in
appendix) The structures are:
-α Linolenic Acid (ALA)
-Eicosapentaenoic Acid (EPA)
-Docosahexaenoic Acid (DHA)
Fatty acids are important for heart and muscle function. Our bodies
cannot make all of the essential fatty acids that we need so we get
them from foods like seed oils, which our body can then convert to
more useful forms. This conversion process is very energetically
expensive.
We can take a short cut and save energy by consuming fish oils,
which are packed full of fatty acids. Fish oils provide a wide range of
health benefits. Such as:
Engage: Students learn what 10 minutes
a lipid is and how they are
useful for our bodies
Explore: Students work in
30 minutes
groups to use a molecule kit
to convert one lipid into
another
Make Sense: Students return 10 minutes
to a large group and review
what they have learned and
learn a new few new facts.
Total: 60
minutes
 Cancer - Anti-cancer effects (particularly breast, colon, and
prostate cancer).
 Cardiovascular - Beneficial for patients with coronary heart
disease, hypertriglyceridemia, secondary cardiovascular
disease prevention, and high blood pressure.
 Mental health - May reduce the risk of depression and suicide.
May help delay or prevent the onset of schizophrenia.
 Alzheimer's disease - May help protect the brain from
cognitive problems associated with Alzheimer's disease.
 Lupus - Reduce lupus disease activity in the skin and joints.
 Psoriasis - Beneficial effects on patients with psoriasis.
Motivating Question: Fatty acids provide our body with long-term
store of energy and health benefits. Converting these fatty acids into
useful forms is energy expensive for our bodies. How does our body
convert fatty acids into useful forms? Using a model for the fatty acid
molecules, can you explain why the conversion is energy expensive?
How does taking a fish oil supplement help or hurt this process?
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4-H Summer Science 2012-Lipids
Preparation (30 minutes)
 Prepare a premade model of Alpha Linolenic Acid (ALA) form the chemistry kits; prepare one
model for each group. Give each group extra pieces to complete their task.
 Prepare a handout for each group that includes the chemical formula, and the chemical structure
of Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA); use a double sided handout
with one compound on one side and the other on the opposite side.
 A PowerPoint presentation could be useful to show diagrams to the whole group and provide
them with information.
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4-H Summer Science 2012-Lipids
Engage (10 minutes)
 Start of this discussion by asking the students some questions
about food, some sample questions could be:
 Why do we eat food?
 What are the sources of energy?
 3 main sources of energy:
 Carbohydrates (less than a day’s worth of
energy)
 Protein (Not used to store energy)
 Fats/Oils (Long term use over weeks)
 Discuss with the students some of the benefits of having energy
stored of the long term storage.
 Fats/Oils:
 Fatty acids provide 85% of energy need of muscles
 Primary fuel for heart
 They are synthesized in our livers then they are
transported into blood.
 Ask the students if they believe that we can make all the fatty
acids we need?
 No, the essential fatty acid ∝-Linolenic Acid (ALA) from
seed oils. (rapseed/canola, soybean, walnut,
flaxseed/linseed, perilla, chia and hemp)
 ALA is synthesized into Eicosapentaenoic acid (EPA) and
Docosahexaenoic acid (DHA): Not synthesized efficiently
 EPA: anti-inflammatory antineoplastic and chemo-preventive
activity (inhibit growth and spread of cancerous cells and prevent
disease)
 DHA: Primary structural component of human brain cerebral
cortex (40%), retina (60%), semen, testicles
 Tell the students that they are going to explore how their body
creates EPA and DHA from ALA by preforming an activity.
Tip: This can be a lot of
information for students to take in,
a poster or PowerPoint presentation
might make it easier for them
understand.
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4-H Summer Science 2012-Lipids
Explore (30 minutes)
 Begin this activity by breaking the group into two equal
size groups (the groups should have between 2-4
members).
 Explain to the students that they are going to be learning
how the body converts ALA to EPA and DHA.
 To do so tell the students they are going to use a model
kit to convert a premade model of ALA to either EPA or
DHA.
 Before you let the students being converting ALA into
their chosen lipid make sure you explain to them all of
the different parts of the model and what they represent.
Every model kit is different, so be sure to do this.
 Have one group convert ALA to EPA and have one
group convert ALA to DHA.
 Give each group a premade model of ALA, making sure
to include extra model pieces so that they have enough
pieces to complete the conversion and a handout with a
diagram with the molecular formula and a diagram of
what the converted compound looks like. A sample
handout can be found in the appendix.
 Let the students work in their group to complete this
task.
 If the students are having trouble converting their
compound you could use these sample questions to get
them thinking about their task:
o What is different between ALA and the
compound you are trying to make?
o What do you need add/take away to get there?
 Let the students work in their groups until they are
finished or you start to run low on time.
Note: If you do not have access to
a molecule kit, you can use
Styrofoam spheres from a local
craft store to represent different
molecules and pipe- cleaners to
represent bonds. Spray paint the
spheres different colors to represent
the different molecules: Carbon,
Hydrogen, and Oxygen.
Tip: To get the students thinking
include a few extra pieces.
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4-H Summer Science 2012-Lipids
Make Sense (10 minutes)
 Bring the students back together as one large group. Review with the students that the point of the
task they completed was to show the conversion of ALA to either EPA or DHA.
 Have a member of each group show their completed model to the whole class, so that everyone has a
change to see what a completed model looks like.
 After everyone has had the opportunity to see what each model looks like. Have the students
discuss as a group what they need to do in order to complete the task.
o What did they need to do to convert ALA to EPA/DHA?
o Can they describe the difference between these 3 fatty acids?
o How about any similarities?
 Some differences that should be noted are:
o The number of carbon/hydrogen atoms in each fatty acid is different
 ALA: has a formula of C18H30O2
 EPA: has a formula of C20H30O2
 DHA: has a formula of C22H32O2
o The number of double bonds increases
 ALA: 3 double bonds
 EPA: 5 double bonds
 DHA: 6 double bonds
 One thing to note that is similar between these 3 fatty acids is that each one has a carboxylic acid
group attached to the end of the chain.
 Explain to the students that our body can create EPA and DHA, but it is a very energy expensive
process, because of the amount of bonds that need to be broken and created. When bonds between
to molecules are formed energy is need to complete the process, when bonds between to
molecules are broken energy is released from the bond and it can therefore not be used to help
the body function. Have the students reflect on why this is not efficient. Do they know of a
better way for us to get EPA and DHA?
 Explain that EPA and DHA are found directly in fish oils, so by taking a fish oil supplement we
provide our body with these essential fatty acids without our body having to do all the work , thus
saving energy. Many companies are now including fish oil supplements in products we use every
day.
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4-H Summer Science 2012-Lipids
Appendix
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4-H Summer Science 2012-Lipids
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4-H Summer Science 2012-Lipids
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