Lipids

1
Lipids

• Triglycerides
• Phospholipids
• Sterols

2
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)

3
Characteristics of Lipids

• Composed of Carbon, Hydrogen, and Oxygen
• Greater than 21 ratio of HO
• Includes fats, oils, phospholipids, and
  cholesterol
• Building blocks are fatty acids and glycerol.
• Energy storage molecules
• Phospholipids part of cell membrane

4
Fatty Acid Structure

• Carboxyl group (COOH) forms the acid.
• R group is a hydrocarbon chain.

5
A Representative Fatty Acid
6
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

7
Saturated vs. Unsaturated

• Saturated - Saturated fatty acids carry the
  maximum possible number of hydrogen atoms.
• .

Stearic acid, an 18-carbon saturated fatty acid
8
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
9
Saturated vs. Unsaturated

• Polyunsaturated fatty acids (PUFA)
• have at least two double bonds.

Linoleic acid, an 18-carbon polyunsaturated fatty
acid
10
Saturated and Unsaturated Fatty Acids Help Shape
Foods
11
Unsaturated Fatty Acid
Saturated Fatty Acid
12
Glycerol
An alcohol composed of a three carbon chain.
13
Synthesis of a Fat
14
Triglycerides

• TG (fats and oils) composed of 3 fatty acids
  attached to a glycerol

15
TG
16
Phospholipids

• Phospholipids
• 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

17
Phospholipids
18
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

19
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.

20
Sterols