What are lipids?
Fats and oils
What elements do lipids consist of?
Carbon, hydrogen and oxygen
Why are lipids insoluble in water?
Because they are polar molecules due to the even distributions of the electrons in the outer most shells of the molecule (so their is no positive or negative areas).
What are the three lipids you need to know?
Triglycerol, phospholipids and sterols
What kind of molecules are lipids?
What are macromolecules?
Giant covalent crystals
What do triglycerols consist of?
one glycerol molecule combined with three fatty acids
Glycerol is a member of a group of molecules called...
fatty acids are members of a group of molecules called...
Describe the structure of the group carboxylic acid
They have a carboxyl group (-COOH) that is attached top a hydrocarbon chain
What is the name of the reaction when a triglycerol is formed from one glycerol molecule combined with three fatty acids
What kind of reaction is an esterification?
A condensation reaction
Draw a diagram of a glycerol
Draw a diagram of a fatty acid
What is the name of the bond that is formed between a glycerol and a fatty acid
An ester bond
After the formation of tryglycerol what other molecule is formed?
3 water molecules
Draw a diagram of an esterification reaction between 1 glycerol and 3 fatty acids
What is the opposite of a condenstaion reaction?
What are saturated fatty acid chains?
Fatty acid chains that have formed the maximum number of bonds with hydrogen atoms, and so contain no double bonds.
What are unsaturated fatty acid chains?
Fatty acids with double bonds between some of the carbon atoms (and therefore are not saturated with hydrogen)
What is the name of a fatty acid chain with just one double carbon-carbon bond?
monounsaturated fatty acid
What is the name of a fatty acid chain with two or more carbon-carbon double bonds?
polyunsaturated fatty acid
What is the structure of an unsaturated fatty acid chain? How does this relate to their properties?
The presence of a carbon-carbon double bond makes the molecule kink. Due to this they cannot pack so closely together and so are liquid at room temperature (oils)
What kind of triglycerides do plants contain?
What kind of health problems can occur due to excess consumption of fat (especially saturated fats)
obesity and heart problems (such as coronary heart disease)
What are phospholipids?
Triglycerides that contain the element phosphorus. One of the fatty acid chains are replaced with a phosphate group.
What is the symbol for the phosphate ion?
What ion is found inside the cytoplasm of all cells?
How comes the phosphate ions are soluble in water?
The phosphate ions have extra electrons and so are negatively charged
Draw a simplified diagram of a phospholipid