LIPIDS (FATS)
Triglycerides and phospholipids are two groups of lipid.
Triglycerides are formed by the condensation of one molecule of glycerol and
three molecules of fatty acid.
A condensation reaction between glycerol and a fatty acid (RCOOH) forms an
ester bond.
The R-group of a fatty acid may be saturated or unsaturated.
In phospholipids, one of the fatty acids of a triglyceride is substituted by a
phosphate-containing group.
The different properties of triglycerides and phospholipids related to their
different structures.
The emulsion test for lipids.
Students should be able to:
•• recognise, from diagrams, saturated and unsaturated fatty acids
•• explain the different properties of triglycerides and phospholipids.
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Identify the two types of Lipids
What are the components of each
type of lipid?
What are the properties of the lipids?
What are the functions/roles of
lipids?
Outcomes:
- name the two types
of lipids.
https://www.youtube.com/
watch?v=eB793h16R8A
- Outline using
diagrams how
triglycerides are
formed from its parts
- describe and explain
the difference
between saturated
and unsaturated lipids.
- discuss the roles of
triglycerides
Triglycerides
Outcomes:
- name the two types
of lipids.
- Outline using
diagrams how
triglycerides are
formed from its parts
- describe and explain
the difference
between saturated
and unsaturated lipids.
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1 molecule of glycerol
3 molecules of fatty acids joined by
condensation reactions
- discuss the roles of
triglycerides
Roles of Triglycerides:
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Energy source (lipids contain twice
the energy content as
carbohydrates)
Waterproofing (lipids are insoluble,
some plants have a waxy cuticle to
keep out the water from leaves)
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A good term to use is hydrophobic
Insulation (fats are slow conductors
of heat and good insulators to
retain heat)
Protection (fats are often stored
around internal organs to protect
them)
Outcomes:
- name the two types
of lipids.
- Outline using
diagrams how
triglycerides are
formed from its parts
- describe and explain
the difference
between saturated
and unsaturated lipids.
- discuss the roles of
triglycerides
Saturated fats vs Unsaturated fats
The fatty acid chains don’t always
have to be the same length.
 Different fats have different length
of the fatty acid.
 Also sometimes they chains have
double bonds in
Outcomes:
- name the two types
of lipids.
- Outline using
diagrams how
triglycerides are
formed from its parts
- describe and explain
the difference
between saturated
and unsaturated lipids.
- discuss the roles of
triglycerides
Plenary: Whiteboards
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What are the 2 types of lipids?
Name the components of a triglyceride
Draw a simple triglyceride
What reaction joins the components
together?
Why would we say that lipids are not
polymers
2 roles of lipids/fats?
What do the terms: Saturated, unsaturated
and polyunsaturated mean?
What state are polysaturated fats? Why is
this?
What state are saturated fats likely to be?
Outcomes:
- name the two types
of lipids.
- Outline using
diagrams how
triglycerides are
formed from its parts
- describe and explain
the differences
between saturated
and unsaturated lipids.
- discuss the roles of
triglycerides
Lets get started: Quick recall test
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Answer the questions in the back
of your notes.
Outcomes:
- name the two types of
lipids.
- Outline using diagrams
how phopholipids are
formed from its
monomers
-explain the properties
of phospholipids and
link to their function
- use the emulsion test to
identify the presence of
lipids in solutions.
Phospholipids
Outcomes:
- name the two types of
lipids.
- Outline using diagrams
how phopholipids are
formed from its
monomers
-explain the properties
of phospholipids and
link to their function
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1 molecule of glycerol
2 fatty acids joined by condensation reactions
1 phosphate group joined instead of a fatty
acid by condensation reactions.
- use the emulsion test to
identify the presence of
lipids in solutions.
Phospholipids - properties
Outcomes:
- name the two types of
lipids.
- Outline using diagrams
how phopholipids are
formed from its
monomers
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The phosphate group is hydrophilic (polar)
The fatty acids are hydrophobic (non polar).
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http://www.johnkyrk.com/cellmembrane.html
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-explain the properties
of phospholipids and
link to their function
- use the emulsion test to
identify the presence of
lipids in solutions.
Test for Lipids (Lab books)
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Title: Testing for Lipids
Aim: to identify which food
substances contain high lipid
content.
Method: Write yourself
Risks: Write yourself
Results table: similar to the tests for
sugars (adapt from this)
Conclusions: Sum up which foods
contain high fat content and how
you could tell.
Outcomes:
- name the two types of
lipids.
- Outline using diagrams
how phopholipids are
formed from its
monomers
-explain the properties
of phospholipids and
link to their function
- use the emulsion test to
identify the presence of
lipids in solutions.
Plenary – Summary Questions
Fats and oils make up a group of
lipids called __ which when
hydrolysed form their
components____ and fatty acids. A
fatty acid with more than one C=C
(double bond) is called ___. In a
phospholipid, the number of fatty
acids attached is __. These are
described as ___ because they repel
water. Phospholipids are used in
creating the ___ because they are
____.
Outcomes:
- name the two types of
lipids.
- Outline using diagrams
how phopholipids are
formed from its
monomers
-explain the properties
of phospholipids and
link to their function
- use the emulsion test to
identify the presence of
lipids in solutions.