Lipids (B) Flashcards
Triglycerides and phospholipids
Describe the structure of a triglyceride
3 fatty acids joined to 1 glycerol molecule
In the condensation reaction between a glycerol molecule and a fatty acid what bond is formed?
An ester bond
Describe the formation of a triglyceride
They are joined in 3 separate condensation reactions with the loss of three water molecules
How many ester bonds are in a triglyceride molecule
3 ester bonds
Glycerol + 3 fatty acids →
Triglyceride + 3 water
What are the properties of triglycerides
- Contain many carbon-hydrogen bonds, releasing twice the energy of carbohydrates during aerobic respiration.
- High hydrogen-to-oxygen ratio, releasing water during respiration, this is vital for desert organisms
- They are non-polar and insoluble in water, making them ideal for energy storage as they are osmotically inactive
- Are present in the waxy cuticle of insects and plant leaves where their insolubility helps to reduce water loss
What are phospholipids?
Lipids containing a phosphate group
How are these molecules joined?
A condensation reaction
What molecules are phospholipids made up of?
One glycerol molecule, two fatty acid molecules and one phosphate group
What bonds does the condensation reaction form?
Ester bonds
What is unique about phospholipid molecules?
They have a polar hydrophilic head containing the phosphate group and a non polar hydrophobic tail consisting of the long fatty acid chains
What does hydrophilic mean?
Attracting water
Where are bilayers formed?
In cell membranes
What does hydrophobic mean?
Repelling water
What are the two types of layers that phospholipids can form?
Monolayers and bilayers
