Lipids Triglycerides Phospholipids Sterols Lipids Lipids are a class of nutrients that includes: –Triglycerides (fats and oils) –Phospholipids –Sterols.
Post on 17-Jan-2016
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Lipids
TriglyceridesPhospholipids
Sterols
Lipids• Lipids are a class of nutrients that includes:
– Triglycerides (fats and oils)– Phospholipids – Sterols– Waxes
• Composed of carbon, hydrogen, and oxygen.
• Lipids are hydrophobic (insoluble in water)
Characteristics of Lipids
• Composed of Carbon, Hydrogen, and Oxygen
• Greater than 2:1 ratio of H:O• Includes fats, oils, phospholipids, and
cholesterol• Building blocks are fatty acids and
glycerol.• Energy storage molecules• Phospholipids part of cell membrane
Fatty Acid Structure
•Carboxyl group (COOH) forms the acid.•“R” group is a hydrocarbon chain.
A Representative Fatty Acid
Fatty Acids• Fatty acids vary in carbon chain lengths, degree
of unsaturation, and number of double bonds. – Degree of Saturation- Saturation affects the
physical characteristics of the fat and its storage properties
Saturated vs. Unsaturated• Saturated - Saturated fatty acids carry the maximum
possible number of hydrogen atoms.
• .
Stearic acid, an 18-carbon saturated fatty acid
Saturated vs. Unsaturated• Unsaturated – Unsaturated fatty acids have
at least one double bond. There are 2 types– Monounsaturated fatty acid (MUFA)
Oleic acid, an 18-carbon monounsaturated fatty acid
Saturated vs. Unsaturated
• Polyunsaturated fatty acids (PUFA)– have at least two double bonds.
Linoleic acid, an 18-carbon polyunsaturated fatty acid
Saturated and Unsaturated Fatty Acids Help Shape Foods
SaturatedFatty Acid
UnsaturatedFatty Acid
Glycerol
An alcohol composed of a three carbon chain.
Synthesis of a Fat
Triglycerides
• TG (fats and oils) – composed of 3 fatty acids attached to a glycerol
TG
PhospholipidsPhospholipids
• contain glycerol, 2 fatty acids and a phosphate
group.
• Soluble in both water and fat
• Roles of phospholipids
– Transport lipids through Plasma membrane
– Make up the cell membrane
Phospholipids
Sterols• Sterols
– cholesterol, vit D, testorone– Multiple carbon-ring structure.– Found in plant and animal foods– Cholesterol is found in animal foods only -
meat, eggs, fish, poultry and dairy products
Sterols• Roles of sterols
– Needed to make bile acids, sex hormones, adrenal hormones and vitamin D
– Component of cell membranes– Cholesterol forms deposits in the
artery wall causing artherosclerosis.
Sterols
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