BPK 110 Lecture Notes - Polyunsaturated Fatty Acid, Conjugated Linoleic Acid, Trans Fat
27 Jul 2012
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Kin 110 Chapter 5 Reading
Lipids
Triglycerides: fats we associate with fried foods, cream cheese, salad dressing, ect.
Are one type of a larger group of compounds called lipids.
Cholesterol: makes a small contribution to the total amount in your body
What are lipids?
Lipids: applies to a broad range of organic molecules that dissolve easily in organic
solvents such as alcohol, but less soluble in water
Hydrophobic lipids: averse to water, water-fearing
Lipophilic: soluble in fat, fat-loving
Hydrophilic: water-soluble, attracted to water
Lipophoblic: fat fearing
Main classes of lipids: triglycerides, phospholipids, and sterols
o Triglycerides: largest category of lipids
Fat cells store them in adipose tissue
Fats and oils
o Phospholipids: 2 percent of dietary lipids
Found in plant and animal origin
Soluble in both fat and water
Crucial roles in cell membranes and blood and body fluids
o Sterols: includes cholesterol
Hydrocarbons with several rings in their structure
Fatty Acids:
Fatty acids are key building blocks:
Fatty acids: determine the characteristics of fat, whether it is solid or liquid at room
temperature.
o Not joined to a tyglercide are called “free” fatty acids
o Chains of carbon atoms with organic acid group (-COOH) at one end and methyl
group (-CH3) at the other
Chain length: the number of carbons that a fatty acid contains. 4-24 carbons, most
have an even number
o the shorter the chain length, the more liquid the fatty acid, more water soluble
as well
Saturation:
o Each carbon atom as four bonds,
o Saturated fatty acids: a fatty acid completely filled by hydrogen with all
carbons in the chain linked by single bonds. (H-C-C-C-H) [solid at room
temperature]
o Unsaturated fatty acid: if carbons are connected by a double bond (C=C), there
are few bonds to hold hydrogen. less saturated with hydrogen
o Monounsaturated fatty acid: carbon chain contains one double bond
o Polyunsaturated fatty acid: carbon chain contains two or more double bonds
[thin liquid at room temperature]
Geometric and Positional Isomers
o CIS fatty acids: hydrogens next to double bonds are on the same side of the
carbon chain. CIS is bent.
o Trans fatty acids: most commonly found in hydrogenated fats, such as those in
stick margarine, and deep fat fried food. Hydrogens surrounding a double bond
are on opposite sides of the carbon chain, straightens the chain and fatty acid
becomes more solid
o Hydrogenation: chemical reaction where hydrogen atoms are added to carbon -
carbon double bonds, converting them to single bonds. Reduces number o f
bonds, making them more saturated
o Conjugated linoleic acid: polyunsaturated fatty acid in which the position of
the double bonds has moved, so a single bond alternates with two double bonds
Omega-3, omega-6, and omega-9 fatty acids
o Omega-9 fatty acid: polyunsaturated acid where the first double bond starting
from (CH3) end of the molecule lies between the ninths and tenth carbon atoms
o Omega-6 fatty acid: first double bond starting from (CH3) end of the molecule
lies between the 6th and 7th carbon atoms
o Omega-3 fatty acid: first double bond starting from (CH3) lies between 3rd and
4th atoms
o ALL these acids can be burned for energy
Nonessential and essential fatty acids:
o Elongation: addition of carbon atoms to fatty acids to lengthen them into new
fatty acids builds storage and structural fats
o Desaturation: insertion of double bonds into fatty acids to change them into a
new fatty acid (omega-9: remove H from carbons 9 and 10 and create a double
bond at C9)
o Essential fatty acids: fatty acids the body needs but cannot synthesize, must be
obtained from food. i.e. cannot manufacture omega-6 or 3
o Nonessential fatty acids: your body can make them when they are needed. Not
necessary to consume them in the diet.
Building Eicosanoids, Omega-3, and Omega-6 Acids
o Eicosanoids: class of hormone-like substance formed in the body from long-
chain fatty acids (regulators, influence on promoting inflammatory processes,
promoting blood clotting)
o Omega-6 Fatty Acid:
Linoleic acid – 18 carbon essential acid with two double bonds is the
many omega-6 fatty acid
Bodies convert to 20:4 with elongation and desaturation
Document Summary
Triglycerides: fats we associate with fried foods, cream cheese, salad dressing, ect. Are one type of a larger group of compounds called lipids. Cholesterol: makes a small contribution to the total amount in your body. Lipids: applies to a broad range of organic molecules that dissolve easily in organic solvents such as alcohol, but less soluble in water. Main classes of lipids: triglycerides, phospholipids, and sterols: triglycerides: largest category of lipids. Fat cells store them in adipose tissue. Fats and oils: phospholipids: 2 percent of dietary lipids. Crucial roles in cell membranes and blood and body fluids: sterols: includes cholesterol. Hydrocarbons with several rings in their structure. Chain length: the number of carbons that a fatty acid contains. 4-24 carbons, most have an even number: the shorter the chain length, the more liquid the fatty acid, more water soluble as well.
