Lipids

A Family of Hydrophobic Macromolecules

Lipid Facts

•  Fat: 

• Oil: 

• Contribute 30-50% of calories for Americans

• .

• Lipids are primarily consumed for energy • Diverse groups:

Lipid Facts Continued

• . .

Types of Lipids 4 major sub-groups:1) Glycerides (fats)2) Phospholipids3) Steroids4) Waxes

• Lipid + Carbohydrate =(cell signalling and attaching)

• Lipid + Phosphate =(cell membranes)

• Lipid + Protein = (cell signalling, structure, attaching)

Lipids Attached to…

Function1. .

2. .

3. .

4. Structural:

5. Vitamins and Hormones

6. Waxes:

Glycerides (Fats)• .

• .

• Glycerides are defined by their fatty acid components:– Number (1 to 3 fatty acid)– Length– Degree of saturation (referring to if double bonds between carbons

are present or not)

Glycerol

• .

• .

GLYCEROLSource:http://en.wikipedia.org/wiki/Image:Glycerin_Skelett.svg

Fatty Acids• .

• Usually hydrophobic (can be amphipathic)

• Monglycerides = 1 fatty acid

• Diglycerides = 2 fatty acids

• Triglycerides = 3 fatty acids

Naming Glycerides

Fatty Acid Nomenclature

Based on:

• Number of carbons

• Number of double bonds

Oleic Acid

Saturated • . • .• . • .• Implicated in coronary heart disease (CHD) • Meats, dairy

Unsaturated • .• .• .• .

• Less stable to off flavor development • Vegetables, legumes, fish

• Polyunsaturated: 

• Highly Unsaturated: 

• Omega 3 Fatty Acids – Good for reducing CHD – High in fish

Linolenic Acid, an Omega 3 Fatty Acid

Unsaturated Fatty Acids• .

• .

• Trans double bonds– .– .– .

• Cis double bonds– .– .– .

Saturated: only single bonds

Unsaturated: double bonds between 1 or more carbons

Formation of a triglyceride

Phospholipids • .• .• .• Cell membrane• Amphipathic:

– Phosphate head = hydrophillic– Fatty acid tails = hydrophobic

Source:http://en.wikipedia.org/wiki/Image:Phospholipid.svg

• Form micelles, liposomes or bilayers in water

• Cell membranes (selectively permeable) are composed of bilayers of phospholipids.

Source:http://en.wikipedia.org/wiki/Image:Cell_membrane_detailed_diagram.svg

LIPIDS

Steroids• .

• .

• .

• Also a membrane component

CHOLESTEROLSource:http://en.wikipedia.org/wiki/Image:Cholesterol.svg

PROGESTERONESource:http://en.wikipedia.org/wiki/Image:Progesterone-2D-skeletal.png

TESTOSTERONESource:http://en.wikipedia.org/wiki/Image:Testosterone_structure.png

Source:http://upload.wikimedia.org/wikipedia/en/b/b0/Steroidfromcholesterol.PNG

Steroids made from Cholesterol

Cholesterol

Why is cholesterol important in the body?

• . • .• . • .

Foods high in cholesterol • Organ meats • Eggs • Shellfish

CONNECTION

Anabolic steroids pose health risks• Anabolic steroids are natural and synthetic

variants of the male hormone testosterone– Build up bone and muscle mass– Can cause serious health problems

(4 ring compounds)

Waxes

• Extremely hydrophobic

• Cutin: cuticle of leaf

Function and Structure of LipidsLipid Molecule Function Structure

Glycerides

Phospholipids

Steroids