Lipids Flashcards
(19 cards)
What are lipids?
Lipids are organic molecules mainly made up of two main types of lipids: triglycerides and phospholipids
What are triglycerides composed of?
Triglycerides are composed of three fatty acids attached to a glycerol molecule
How are triglycerides formed?
Triglycerides form through three condensation reactions between one glycerol molecule and three fatty acid chains. Involving three water molecules being removed and the formation of ester bonds
What type of bond is formed from the condensation reaction in triglycerides?
Triglycerides form ester bonds
What is the two ways fatty acids can vary?
Fatty acids can vary in length and fatty acid chain type. Fatty acid chains can be saturated and unsaturated
What is a saturated fatty acid chain?
A saturated fatty acid consists of no double bonds within their hydrocarbons
What is a polyunsaturated fatty acid?
A fatty acid chain consisting of two or more double bonds between the hydrocarbons
What is an unsaturated fatty acid? What are the two different types?
An unsaturated fatty acid contains at least one or more double bonds within their hydrocarbons.
The two possible types of hydrocarbon are mono or poly - unsaturated fatty acids
What is a monounsaturated fatty acid?
A fatty acid consisting of one double bond between the hydrocarbons
Name some structural features of triglyceride that result in some of its properties
- Triglyceride has a large ratio of energy storing carbon - hydrogen atoms. Which results in a lot of energy being stored in the molecule
- Triglycerides are long and hydrophobic, making them insoluble - do not affect water potential and do not cause osmotic water uptake
- Triglycerides are a metabolic water source. When they are oxidised water is released, allowing it to act as source of water for animals in the desert
Where does the ester bond form in triglycerides?
An ester bond forms between the hydroxyl group (-OH) on glycerol and the carboxyl group -(COOH) of the fatty acid
How is the ester bond formed in phospholipids?
Two fatty acids bond to the glycerol molecule through two condensation reactions to form the two ester bonds
What are phospholipids composed of?
Phospholipids are composed of a glycerol molecule, a phosphate group and two fatty acid chains
Describe the hydrophillic head
The hydrophilic head repels fats and attracts water since it is charged
Why are the fatty acid chains described as hydrophobic?
The fatty acid chains repel water but will attract fats, mixing with them
Why is the head of the phospholipid called hydrophilic?
The head is called hydrophilic because of the negative charge on the phosphate group
What do phospholipids form?
Phospholipids form a phospholipid bilayer membrane structure
How are phospholipids positioned in water?
In water, phospholipids have their hydrophilic heads facing the water and their tails facing each other so they are not exposed to the water
What are the similarities between phospholipids and triglycerides?
- Both contain a glycerol molecule
- Both may be attached to a mixture of saturated, monounsaturated and polyunsaturated fatty acids
- Both contain the elements carbon, hydrogen and oxygen
- Both are formed by condensation reaction
