1.6 Lipids: Introduction Flashcards
The roles of lipids in living organisms The difference between saturated and unsaturated fatty acids How to test for lipids
What elements are found in lipids?
- carbon (C)
- hydrogen (H)
- oxygen (O)
(and some lipids may also contain phosphorus (P))
Are lipids polymers?
No
What are the main functions of lipids?
There are 5
- Energy supply - Lipids can be oxidised to provide energy to cells.
- Structural components - Phospholipids are used in cell membranes.
- Waterproofing - Insoluble lipids are used to form water-resistant barriers.
- Insulation - Lipids can help retain heat or act as electrical insulators.
- Protection - Delicate organs are surrounded by a layer of fat.
What are most lipids made of?
Fatty acids and glycerol
What is the structure of a fatty acid?
Carboxyl group attached to a hydrocarbon chain
What are the two types of fatty acids?
Saturated and unsaturated
What are saturated fatty acids?
Fatty acids with no carbon-carbon double bonds
What are unsaturated fatty acids?
Fatty acids with at least one carbon-carbon double bond
What is the difference in melting point between saturated and unsaturated fatty acids?
Saturated have higher melting points
What state are saturated fatty acids at room temperature?
Solid (fats)
What state are unsaturated fatty acids at room temperature?
Liquid (oils)
What is a monounsaturated fatty acid?
A fatty acid with one double bond
What is a polyunsaturated fatty acid?
A fatty acid with two or more double bonds
How do you test for lipids?
Add ethanol
What is a positive result for lipids?
A milky white emulsion
