Lipids Flashcards
(20 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
Draw the structure of a triglyceride molecule
Draw out answer and check back your work
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 has a hydrocarbon chain which only has single bonds between its carbons
What is a polyunsaturated fatty acid?
A polyunsaturated fatty acid chain has two or more double bonds between its carbons within the hydrocarbon chain
What is an unsaturated fatty acid? What are the two different types?
An unsaturated fatty acid is a hydrocarbon chain which consists of at least one double bonds between its carbons
The two possible types of hydrocarbon are mono or poly - unsaturated fatty acids
What is a monounsaturated fatty acid?
A fatty acid consisting of only one double bond between its carbons
Name the structural features of triglyceride that result in its properties
Hint: 4pts, energy, source of ….., water potentials, mass + movement
- Trigylceride has more energy storing carbon - hydrogen bonds than carbon atoms , so a lot of energy is stored in the molecule
- Triglycerides have a high ratio of hydrogen - oxygen atoms that act as a metabolic water source, allowing triglycerides to release water when they are oxidised.
- Triglycerides do not affect water potentials and osmosis, this is because they are large and hydrophobic, making them insoluble in water
- Lipids have a relatively low mass. Therefore a lot can be stored without increasing the mass of an organism, or preventing its movement
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
Draw the structure of a phospholipid molecule, specify where the hydrophilic head and hydrophobic tails
Check answer on freeform
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 described as hydrophilic because of the negative charge on the phosphate group, which attracts water and repels fats
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
