Lipids Flashcards
What are lipids?
Non-polar macromolecules. Including fats and oils.
The electrons in their outer shell are evenly distributed, making them insoluble
What is a triglyceride?
A lipid, made of one glycerol and 3 fatty acids.
Consist of a caboxylic+hydrocarbon
CONDENSATION REACTION
How do glycerol and fatty acids come together?
Hydroxyl groups interact, producing 3H20 and 3 ester bonds.
What is a phospholipid?
A modified triglyceride containing P as well as H C O
What are the 6 main roles of lipids?
- Membrane formation
- Hormone production
- Waterproof layer(because fat is hydrophobic)
- Protect internal organs(good shock absorber)
- Energy store(very dense, yield 2x more/g than carbs)
- Thermal insulation(bad heat conductor)
What are saturated fats?
- Single bonds which pack tightly
- All carbon atoms form max number of bonds
- Solid at room temp(common in warm environments)
What are unsaturated fats?
- Double bonds, causes kinks meaning it cant pack as tightly
- Makes bilayer more mobile
- Liquid at room temp(common in cooler environments)
What are the 2 types of unsaturated fats?
Monounsaturated- One double bond between carbons
Polyunsaturated- More than one double bond between carbons
What are sterols?
-Lipids containing 4 rings of carbon atoms
-Hydroxyl group is hydrophilic, rest is hydrophobic(similar to phospholipid in this respect)
Where is cholesterol created?
In the liver and intestines
What role does cholesterol play in cell membranes?
Regulates fluidity and prevents them from becoming too fluid in warm temperatures
What does cholesterol help to make?
Other steroids eg,
-Vitamin D
-Hormones
-Bile
All are fat soluble, easier to pass phospholipid bilayer
What is the test for lipids?
EMULSION TEST.
- Sample is mixed with ethanol
- Resulting sample is mixed with water, shake
Positive= white emulsion on top of solution
Negative= clear solution
