Lipids Flashcards
What are the two groups of lipids
Triglycerides and phospholipids
How are Triglycerides formed
Condensation of 1 molecule of glycerol + 3 molecules of fatty acids
What does a condensation reaction between glycerol and a fatty acid (RCOOH) form
An ester bond
Is the R-group saturated or unsaturated
Both
What happens in a phospholipid compared with triglycerides
1 fatty acid of a triglyceride is substituted by a phosphate-containing group
What are the different properties of triglycerides and phospholipids related to
Their different structures
Features x2 of triglycerides (two words)
Non-polar
Hydrophobic
What are the monomers of Triglycerides
Glycerol
Fatty acid
Shorthand formula of a fatty acid
RCOOH
How can fatty acids vary
Length of hydrocarbon chain
Saturate or unsaturated( double bond c=c)
Are the tails hydrophilic or hydrophobic in a triglycerides
Hydrophobic
If something is hydrophobic does it dissolve in water?
No it’s insoluble
What type of reaction is an ester bond forming
Condensation
How many ester bonds are needed to form a triglycerides
3
Structure of a phospholipid
Phosphate group
Glycerol
2 fatty acids
Which parts are hydrophobic and hydrophilic on a phospholipid
Hydrophobic tails
Hydrophilic heads
What are triglycerides used for
Energy storage
Structure/ function of triglycerides
Good energy storage- long hydrocarbon tails of fatty acids contain lots of chemical energy - lots of energy released when they are broken down
Insoluble in water - don’t effect osmosis
Test for lipids
Emulsion
Add ethanol then add water
Forms white emulsion
Structure of a fatty acid
O=C——-R
/
OH
Why does using colorimeter improve repeatability of results
Standardise method
Compare and contrast structure and properties of phospholipid and triglycerides x5
- Both contain ester bonds (between glycerol and fatty acid)
- Both contain glycerol;
- Fatty acids on both may be saturated or unsaturated;
- Both are insoluble in water;
- Both contain C, H and O but phospholipids also contain P
- Triglyceride has three fatty acids and phospholipid has two fatty acids plus phosphate group;
- Triglycerides are hydrophobic/non-polar and phospholipids have hydrophilic and hydrophobic region;
Accept ‘non-polar’ for hydrophobic and ‘polar’ for hydrophilic. - Phospholipids form monolayer (on surface)/micelle/bilayer (in water) but triglycerides don’t;
Is cholesterol a lipid
Yes
