Department of Biochemistry
Foundation Module Phase - 1
Soluble in non-polar solvents and insoluble in polar
solvents. Lipids are not polymers.
•They are basic building blocks of lipids(simplest lipids).
•Fatty acids are carboxylic acids.
Q.Fatty Acids are
A.Because they have both
polar(hydrophilic) and non-
in their structure
Classification of fatty acids
Q. What is the chemical
difference between saturated
and unsaturated fatty acids?
A. Saturated fatty acids
contain only single
bonds between carbons,
fatty acids contain at
least one double bond.
Corn oil contains 86% polyunsaturated fatty acids
Therefore is a liquid at room temperature.
Olive oil contains monounsaturated fatty
Therefore is a liquid at room temperature,
likely to solidify when refrigerated.
Saturated fatty acids (tropical oils, animal
fats) are solids, or nearly solids at room
Unsaturated fats are preferred over saturated fatty
acids for nutritional reasons.
Q.Would you expect a deep sea fish (living in cold
water) or a shallow water fish (living in warmer
water) to have a higher percentage of unsaturated
fatty acids in its tissues?
Q1.Give some examples for simple
lipids Fatty acids + Alcohol
Q2.Find out some common examples
for complex lipids
Fatty acids + Alcohol+ X
The degree of saturation of a fatty
acid affects particularly the fatty acid
Q3.Unsaturated fatty acids have lower
melting points than saturated fatty acids.
Why is that?
Melting Points and Solubility in Water
of Fatty Acids
Solubility in H2O
A. Fatty acids
which have to be
Q. What are food, as human
essential cells have no
fatty acids? appropriate
Q4.What are the two families of essential
Good sources of ‘omega-3 fatty acids’
• Oily fish
(salmon, mackerel, sardines, tuna)
• Pumpkin seeds, sesame seeds
• soybean oil
Good sources of ‘omega-6 fatty acids’
•Most vegetable oil, Sunflower oil, Corn oil, Soybean oil
•Cotton seeds oil
•Nuts and cereals
Essential fatty acids are used by every cell
in your body.
acids good for
Lipids have four major functions which
are physiologically important for human.
Serve as vitamins and hormones.
Structural components of biological membranes.
synthesize bile acids that
Glycerides (acylglycerols) are esters formed from glycerol
and fatty acids.
Q6.What elements are
found in lecithin and
Q7. Identify a-j
Q9.Name the enzymes A& B.
State the mechanisms by which aspirin and
ibuprofen inhibit PGH2 Synthesis.
•General structure of a steroid – four rings
Q10.What are the
derivatives of steroids?
• Most abundant steroid in the body
• Add methyl CH3- groups, alkyl chain,
and -OH to steroid nucleus
Cholesterol in the Body,
• Cellular membranes
• Myelin sheath, brain,
and nerve tissue
• Bile salts
• Vitamin D
Q11 . Identify each lipid as: (1) phospholipid (2) steroid
(3) triglyceride (4) sphingolipid
B. Glycerol, 2 fatty acids, phosphate, and choline
C. Sphingosine, fatty acid, phosphate, and choline
E. Bile salts
F. Most of plasma membranes
The diagram represents a phospholipid molecule
Q12.Name the following parts of the molecule
What are the main ingredients in your soap?
• One test tube is filled with Sunflower oil (A).
• Coconut oil is placed in a second test tube.(B)
• Add few drops of Hubl’s iodine for each solution.
• Test tubes are shaken.
• After some minutes a spatula full of starch powder is added
to each of the two test tubes.
• The test tubes are again shaken.
Q13.what is the
Foods prepared with edible oil develop a kind of smell
and undergo changes in taste after some time. What is the
reason for this?
Partial hydrolysis of TAG Oxidation of UFA @double
odour + Taste
Health issues associated with lipids
•Unsaturated fat with trans-isomer fatty acid.
•Not essential fatty acids
•Naturally found in animal products where they are
produced by bacteria in the gut of ruminant animals (eg:
cow, goat, sheep)
•Therefore some trans fatty acids are present in meat,
milk and other dairy products.
•These are mostly C18 monounsaturated fatty acid
• Daily intake of 5g trans fat increases the risk of heart
disease by 25%
Trans fatty acids
How are trans fats made
Trans fats are made through the chemical
process called hydrogenation of vegetable oils.
Hydrogenation solidifies liquid oils and
increases the shelf life and the flavour stability
of oils and foods that contain them.
Sun flower oil Margarine
a.Fats: Fatty acids + Glycerol
b. Waxes: Fatty acids + Long chain alcohol
Example Fatty acids Alcohol X
a.Phospholipid Fatty acids Alcohol Phosphoric
ex: acid residue
1.Glycero phospholipid Fatty acids Glycerol
ex: Lecithin acid residue
Fatty acids Glycerol Choline
2.Sphingophospho lipid Fatty acids Sphingosin Carbohydrat
Presence of one or more double bonds in hydrocarbon chain of unsaturated fatty acids
results “ BENDS” in the molecules. These molecules do not stack well. As a result of that
inter-molecular interactions become much weaker than saturated fatty acids leading to
lower melting points.
1. ω-3 (or omega-3 or n-3)
2. ω-6 (omega-6, n-6.)
• Alpha-linolenic acid – a polyunsaturated omega-3 fatty acid
• Linoleic acid -an unsaturated omega-6 fatty acid.
• Control immune system, blood pressure, nervous system,
inflammatory reactions, blood clotting and hormonal
• Regulate a large number of mechanisms including
increasing the fluidity of cell membranes and improving the
ability of selective permeability and help to keep toxin out
and bring nutrients into cells.
• Influence the activation of cell genes and act as second
messengers and produce good eicosanoids.
• Furthermore, a diet rich in EFAs can be helpful in many
diseases( Rheumatoid arthritis, Inflammatory bowel disease)
• a: Oligosaccharide
• b: Glycoprotein
• c: Glycolipids
• d: Head of phospholipid
• e:Tail of phospholipid
• f: Phospholipid bilayer
• g: Filament
• h:Peripheral protein
• i: Cholesterol
• j: Transmembrane protein
Eicosanoids are a family of powerful, hormone-like
produced in the body from essential fatty acids . . .
• They have specific effects on target cells close to their site of
• They are rapidly degraded, so they are not transported to
distal sites within the body.
• Examples: prostaglandins, prostacyclins, thromboxanes,
leukotrienes, epoxyeicosatrienoic acids (EETs).
• Roles in inflammation, fever, regulation of blood pressure,
blood clotting, immune system modulation, control of
reproductive processes & tissue growth, sleep/wake cycle
Aspirin and Ibuprofen (a Non-steroid
anti inflammatory drug) Inhibit PGH2
Note: Aspirin irreversibly acetylates and
thus inactivates the enzyme whereas the
action of Ibuprofen is reversible.
• Steroid hormones
• Vitamin D
Phosphate Glycerol 2 Fatty acids
The sample containing Coconut oil turns intensely blue
In Sunflower oil all the iodine will be consumed.
Consequently no colour change can be observed after the
addition of starch.
Discussion and background:
Sunflower oil contains unsaturated fatty acids.
Iodine adds across the double bonds in an unsaturated bond.
Coconut oil consists mainly of glycerides from saturated fatty
acids (e.g. palmitic and lauric acid).