Chapter 3: Lipid Chemistry Flashcards
What are lipids?
Organic compounds insoluble in water but soluble in organic solvents. Eg. Chloroform, ether, benzene, and acetone.
What is the lipid’s biomedical importance?
They provide the body with a source of energy: lipids have a high energy value.
They provide the body with essential vitamins : vitamins K, E, D, A.
They provide the body with essential fatty acids: Linoleic, and a linoleic acids.
What are the compartments the lipids are found in the body?
Plasma, adipose tissue, and cell membrane.
What are types of lipids?
Simple lipids, conjugated lipids, and derived lipids.
Simple lipids
Esters of fatty acids with alcohols.
Conjugated lipids
Simple lipids conjugated with another group. Eg. Phospholipids or glycolipids.
Derived lipids
Product of hydrolysis of lipids or substance associated with lipids in nature.
Fatty acids
Monocarboxylic organic acids that mostly contain an even number of carbon.
Fatty acids occurrence
Esterified with alcohols: in natural fat, oils, and waxes.
Unesterified: in plasma carried by albumin (FFA).
Fatty acids are classified according to?
Whether they have a double bond or not.
Saturated: contains no double bonds.
Unsaturated: contains I or more double bonds.
Saturated fatty acids
No double bonds.
Types of saturated fatty acids.
Short chain, medium chain, long chain, and very long chain.
Short chain
C2-C4.
Examples: Acetic acid C2
Butyric acid C4
Medium chain
C8-C10
Example: Capric acid C10
Long chain
C12-C22
Examples: Palmetic acid C16
Steric acid C18
Very long chain
C24 or more.
Example: Lignoceric acid C24
Why are the palmitic and stearic acids the most important fatty acids?
Because they are widely distributed in diet.
What is the commonest fatty acid in animals?
Palmitic acid.
What are sources of saturated fatty acids?
Animal fat: cream and butter.
Vegetable products: coconut and Palm oil.
Biomedical importance of saturated fatty acids.
Saturated fats acids increase cholesterol, this leads to increase atherosclerosis. This results in incidence of coronary heart disease (CHD).
What are the two types of double bonds in unsaturated fatty acids?
Cis and trans.
Cis type
Same side of double bond.
Allow bending of the chain at the double bond. The melting temperate is low, so they are liquid in room temperature.
Trans type
Opposite side of the double bond.
Double bonds are linear are solid at room temperature.
Where do naturally occurring unsaturated fatty acids contain?
Double bonds of the cis type.
What is the saturated fatty acids structure at room temperature?
Solid and linear.
How trans fatty acid produced?
It is during the hydrogenation of vegetable oil into margarine.
What are sources of trans fatty acids?
Baked food and cakes.
Trans FA biomedical importance
Saturated fats acids increase cholesterol, this leads to increase atherosclerosis. This results in incidence of coronary heart disease (CHD).
How are fatty acids classified according to their double bones?
Monoenoic ( monoethenoid) and polyenoic (polyethenoid).
Monoenoic (monoethenoid)
Contains only 1 double bond in their structure.
Present in animal and vegetable fat as olive oil.
Monoenoic (monoethenoid) biomedical importance
Decrease plasma cholesterol, this leads to the decrease of atherosclerosis. This results in decrease of incidence of coronary heart disease (CHD).
What are examples of Monoenoic (monoethenoid) double bonds?
- Palmitoleic (16:1; omega 7)
- Oleic (18:1, omega 9)
- Nervonic (24:1; omega 9)
Polyenoic (polyethenoid)
Contains more than 1 double bond.
What are polyethenoids classified according to?
Their number of double bonds. Diethenoid, triethenoid, etc.
Each 2 double bonds are separated by a methylene group (-CH2).
Omega 6 PUFA
1st double bond at carbon 6 in relation to omega carbon.
Examples of omega 6 PUFA
- Linoleic acid (18:2) parent FA
- Arachidonic acid (20:4)
What are sources of omega 6 PUFA?
Nuts, olives, different oils such as sunflower, cotton seed, linseed, and corn oil.
What is the biomedical importance of omega 6 PUFA?
Decrease plasma cholesterol, this leads to the decrease of atherosclerosis. This results in decrease of incidence of coronary heart disease (CHD).
Omega 3 PUFA
First double bond at carbon 3 in relation to omega carbon.
Examples of omega 3 PUFA
- a Linoleic acid (18:3) parent FA
- Timnodonic acid (20:5)
What are the sources of omega 3 PUFA?
Plant oil like flax seed, canola, and fish oil.
Why is the biomedical importance of omega 3 Decrease plasma cholesterol, this leads to the decrease of atherosclerosis. This results in decrease of incidence of coronary heart disease (CHD).?
- Decrease in cholesterol results in decrease in atherosclerosis and coronary heart disease.
- Decrease in blood pressure.
- Decrease in plasma tag.
- Decrease in tendency of thrombosis.
Monoethenoid FA
Plamitoleic, oleic, and nervonic.
Diethenoid FA
Linoleic
Triethenoid FA
a Linoleic
Tetraethenoid FA
Arachidonic
Pentaethenoid FA
Timnodonic
Essential FA
FA that can’t be synthesized in the body and should be supplied in diet.
Essential FA’s are:
Linoleic and a Linoleic.
Other members of omega 3 and 6 are formed from Linoleic and a Linoleic by desaturation and elongation.
Arachidonic becomes essential in the absence of Linoleic.
Timnodonic becomes essential in the absence of a Linoleic.
What does the deficiency of essential FA’s lead to?
Children: retardation of growth and dermatitis.
Adults: fatty liver and sterility.
Ecasanoids
Derivatives of C20 like arachidonic acid and Timnodonic acid. They are hormone like molecules produced by most mammalian cells.