1. Lipids: Not Just Fat
BIOL 103, Chapter 6-1

2. Today’s Topics What are Lipids? Fatty Acids are Key Building Blocks
Triglycerides
Phospholipids
Sterols

3. Lipids Essential nutrients Provide energy
Help transport fat-soluble nutrients
Contribute to flavor and texture of food

4. What are Lipids? Lipids include…
Triglycerides (__________________________)
In body: stored in adipose tissue
In food: “fats and oils”
Phospholipids (_________________________)
Plant and animal origin
Body can make them
Soluble in fat and water
Sterols (_______________________________)
Most well known: Cholesterol

5. Fatty Acids are Key Building Blocks
Determine whether a fat is ________________ at room temperature
Basic structure:
Chain length
____________ Carbon length

6. Fatty Acids are Key Building Blocks
Saturation
Saturated fatty acids
_________________________ between carbons
Unsaturated fatty acids
_______________________________
Monounsaturated fatty acid (MUFA):
_______________________
Polyunsaturated fatty acid (PUFA):
________________________
Fats with more bonds are generally more _____________

7. Fatty Acids are Key Building Blocks
Cis fatty acids
Trans fatty acids
Occurs ________________
Chain is _______________
Produced by ____________ (adds hydrogen to an unsaturated fatty acids)
A small portion of trans fat can occur naturally
Chain is ________________

8. Trans Fat
In health, trans fatty acids are known to raise LDL (“bad”) cholesterol, and lower HDL (“good cholesterol”), promote systemic inflammation, and increase triglycerides in your blood.
History and how it is made:
In Europe (1910): needed a cheaper butter substitute for soldiers
In US (1960s): People wanted to eat a “healthier and cheaper butter”  food scientists decided to hydrogenate vegetable oil to solidify them

9. Fatty Acids are Key Building Blocks
Nonessential and essential fatty acids
Nonessential fatty acids
Can be made in the body
Not “essential” to have in your diet

10. Fatty Acids are Key Building Blocks
Nonessential and essential fatty acids (cont.)
Essential fatty acids
Can’t be made in the body
Must come from food
___________________
_______________________
Used to make eicosanoids

11. Triglycerides Structure Functions ________________________
Energy source: 9 kcal/g
Energy reserve: form of stored energy in _________ ___________________________________________
Insulation and protection:
Visceral fat ____________________________
Subcutaneous fat _________________________________
Carrier of ____________________________
Sensory qualities in food

12. Apple vs. Pear

13. Triglycerides in Food Found in a variety of fats and oils
Classified by their most prevalent type
Saturated fatty acids: _________________ and tropical oils
Polyunsaturated fatty acids: _________________
Omega-3: soybean, flaxseed oils; salmon, tuna
Omega-6: seeds, nuts, corn oil, meat, poultry, eggs

14. What are the positive and negative consequences of hydrogenating a fat
What are the positive and negative consequences of hydrogenating a fat? (Problem Set 6, #3)
Oxidation causes food to spoil and damage body tissues
Pros
Cons
_____________________ _____________________
______________________
______________________ ______________________

15. Phospholipids Structure Functions: _______________________________
Keep fat suspended in water
Keep oil and water mixed
_____________________ for cell membranes
Our bodies can make phospholipids, so we do not to eat them in our diet
Both hydrophobic and hydrophilic
Tails: Hydrophilic
Head: Hydrophobic
Makes it possibly to communicate with the watery environments of blood and cell fluids, yet with a lipid portion that allows other lipids to nter and exit cells.

16. Phospholipids Cell membrane Double layer of phospholipids
Store fatty acids temporarily and release them as needed 
Important role in nerve cells
e.g. Ach

17. Phospholipids Lipid transport Stomach Intestine Blood
Breaks fat into tiny particles for digestion
Intestine
Continues emulsifying fat
Blood
_____________________________________ that carry lipid particles to their destinations in the body

18. Phospholipids Emulsifiers (Lecithin) In body In food
Phospholipid with choline  ___________________
In food
Blend of phospholipids with different nitrogen-containing components
Used as emulsifiers (e.g. salad dressing, chili, sloppy-joe mixes, and chewing gum).

19. Phospholipids Phospholipids in food
Occur naturally in plants and animals
Examples: Egg yolks, liver, soybeans, peanuts
_________________________ because the body can make it

20. Sterols A category of lipids that include cholesterol
Structural characteristics:
____________________

21. Sterols Cholesterol functions:
________________________of cell membranes
Precursor to other substances
Examples: __________________________________, Manufacture bile salts
Cholesterol synthesis in _________________
Sterols in food
Found only in _____________________