Unit 3 - Lipids Flashcards
What are lipids soluble in?
Organic solvents
What is the body’s chief storage place for excess food energy?
Fat
What is the typical fuel mix at rest for the liver and muscles?
50/50 carbohydrate/lipid
The body has limited stores of ____ but unlimited stores of ____
- Glycogen
- Fat
Why does the body have unlimited capacity to store fat?
Because of the fat-storing cells of the adipose tissue
What do fat cells secrete?
Hormones that help to regulate the appetite and influence other body functions
Is fat a good source of glucose?
Nope
What are 4 functions of fat besides energy?
1) Provide oil for skin and scalp
2) Insulate the body from temp. extremes
3) Hard fat protects kidneys
4) Cell membrane constituents that help maintain structure and health of all cells
What are the 3 types of lipids?
1) Triglycerides
2) Phospholipids
3) Sterols
What is the major form of lipid found in the body and in foods?
Triglycerides
What are triglycerides made up of?
3 fatty acids and a glycerol backbone
What is the most important phospholipid?
Lecithin
What are sources of lecithin?
- Eggs
- Liver
- Soybeans
- Wheat germ
- Peanuts
What are phospholipids made of and what does each part do for the molecule?
- Glycerol backbone
- 2 fatty acids that make the phospholipid fat soluble
- 1 phosphate group that enables the phospholipid to dissolve in water
What do phospholipids act as in the body and what does this mean?
Emulsifiers, which keep fats in solution in the watery blood and body fluids
What are sterols?
Large molecules consisting of interconnecting rings of carbon atoms, w/ side chains of C, H, and O
What is the best known sterol?
Cholesterol
Is cholesterol an essential nutrient?
No, it can be made by the body
What are other sterols besides cholesterol?
- Bile
- Vitamin D
- Sex hormones
What are plant sterols?
Phytochemicals that interfere w/ cholesterol absorption in the intestinal tract, therefore lowering blood cholesterol levels
What are sources of sterols?
- Meats
- Eggs
- Poultry
- Dairy products
Where are sterols naturally found (other than cholesterol)?
Plants
How are fatty acids classified?
By chain length and saturation
What are the 3 classifications of fatty acids?
- Saturated
- Monounsaturated
- Polyunsaturated
What does saturation of a fatty acid effect?
Firmness at room temp. and stability
How can you increase the stability of a fatty acid and make it firmer at room temp.?
Hydrogenation
What is the downside to hydrogenation?
Can create trans-fatty acids
What is hydrogenation?
Adding hydrogens to saturate some or all points of unsaturation
Which fatty acids are softer at room temp. and melt easier?
Fats that contain a shorter chain or the more unsaturated fatty acids