Biological molecules - Lipids Flashcards
What are the two main types of lipids?
Triglycerides and phospholipids.
What are triglycerides?
Lipids may by one molecule of glycerol and 3 fatty acids joined together by ester bonds formed in condensation reactions.
What are saturated lipids?
Lipids that don’t contain carbon-carbon double bonds.
What are unsaturated lipids?
Lipids that contain carbon-carbon double bonds.
Why are unsaturated lipids liquids at room temperature?
The molecule bends due to the presence of a double bond. This means unsaturated lipids can’t pack as closely together, making them liquid at room temperature.
How does the structure of triglycerides relate to their function?
- High ratio of energy storing carbon-hydrogen bonds to carbon atoms and therefore an excellent energy store.
- Low mass to energy ratio so a good storage molecule, with a lot of energy being stored in a small volume.
- Large and non-polar so insoluble and will not affect the water potential of cells.
-Release water when oxidised due to high ratio of hydrogen-oxygen atoms. They provide an important water source for animals in dry environments.
What is the structure of a phospholipid?
It is made up of one molecule of glycerol, two fatty acids and one phosphate-containing group.
Why do phospholipids form micelles when in contact with water?
Phosphate heads are hydrophilic and the tails are hydrophobic. This means they are polar and form micelles when in contact with water
How do the properties of phospholipids relate to their function?
- In an aqueous environment being polar means a bilayer can form.
-The hydrophilic heads and hydrophobic tails can be used to form a cell surface membrane. - They can form glycolipids with carbohydrates which are important to the cell surface membrane for cell recognition.
