Lipids Flashcards
1
Q
What do lipids all contain?
A
Hydrocarbons
2
Q
How are triglycerides structured?
A
- One glycerol molecule with three fatty acids attached to it
- Fatty acid tails are hydrophobic, making lipids insoluble in water
3
Q
Saturated fatty acids…
A
Don’t have any double bonds between their carbon atoms. The fatty acid is ‘saturated’ with hydrogen
4
Q
Unsaturated fatty acids…
A
Do have double bonds between carbon atoms, causing the chain to kink
5
Q
How are triglycerides formed?
A
Condensation reactions - ester bonds form between the glycerol and fatty acids
6
Q
What are the lipids found in cell membranes?
A
Phospholipids
7
Q
How are phospholipids structured?
A
- One glycerol molecule, two fatty acids and a phosphate group
- Phosphate group is hydrophilic
- Fatty acid tails are hydrophobic
8
Q
Properties of triglycerides
A
- Lots of energy released when hydrocarbon tails of the fatty acids are broken down
- Insoluble in water
- Bundle together as insoluble droplets in cells
9
Q
Properties of phospholipids
A
- Heads are hydrophilic
- Tails are hydrophobic
- Centre of the bilayer is hydrophobic, so water-soluble substances can’t easily pass through it
10
Q
The emulsion test for lipids
A
Add ethanol to the sample substance and shake, then pour the solution into water. Any lipid will show up as a milky white emulsion
