Lipids Flashcards
(20 cards)
What is a triglyceride molecule made up of?
One glycerol molecule and 3 fatty acid chains.
What is a phospholipid made up of?
1 glycerol, 2 fatty acid chains and a phosphate group.
What reaction forms triglyceride?
A condensation reaction between one molecule of glycerol and 3 molecules of fatty acid chains.
What is produced after the condensation reaction to form triglycerides?
3 ester bonds
3 molecules of water
What are saturated fatty acids?
They have single bonds between atoms.
What are unsaturated fatty acids?
They have at least one double bond between carbons.
What are 4 properties of triglyceride?
Energy Storage
Metabolic water source
Don’t affect water potentials or osmosis.
Can store a lot
Why are triglycerides good energy stores?
They have a large ratio of energy-storing carbon-hydrogen bonds compared to the number of carbon atoms. A lot of energy can be stored in the molecule.
Why are triglycerides good metabolic water sources?
They have a high ratio of hydrogen to oxygen atoms. They can release water if they are oxidised. This is essential to desert animals such as camels.
Why don’t triglycerides affect water potentials and osmosis?
They are large and hydrophobic meaning they are insoluble in water.
Why can triglycerides store a lot?
They have a relatively low mass so a lot can be stored without increasing the mass and preventing movement.
Describe the emulsion test.
Dissolve sample in cold ethanol and shake. Add distilled water and shake. If a white emulsion appears, lipids are present.
Where is the phosphate group in phospholipids attached?
To the glycerol
What reaction produces phospholipids?
Two fatty acids bonds to the glycerol via two condensation reactions resulting in two ester bonds and 2 molecules of water.
What are the 4 properties of phospholipids?
Attracts water
Repels other fats
Repels water
Polar
How do phospholipids attract water?
They have a hydrophilic head that attracts water as it is charged.
How do phospholipids repel water?
The fatty acid chain is not charged. It is known as the hydrophobic tail and repels water but will mix with fats.
How do phospholipids repel other fats?
The phosphate group is charged so it repels other fats.
How are phospholipids polar?
They have two oppositely charged regions.
How do phospholipids form a phospholipid bilayer?
In water they are positioned so that the heads are exposed to water and the tails are not. This forms a phospholipid bilayer membrane structure which makes up the plasma membrane around cells.
