Larger Molecules
Biology: Cambridge International GCSE Supplement, topic 4.1.2
Larger Molecules
Large carbohydrate, protein and lipid molecules are made up of many smaller units. The way that these units are arranged affects the structure and function of these larger molecules.
Carbohydrates
- Glucose is a small carbohydrate (a sugar).
- Cellulose (the substance that gives structure to plant cell walls) is also made up of glucose.
- Starch (a store of energy in plants) is made up of glucose units.
- Glycogen (a store of energy in animals) is made up of glucose.
- Glucose units are arranged differently to make these different molecules.
Proteins
- Proteins are made out of units called amino acids.
- There are different amino acids, and the order of amino acids affects the shape of the protein molecules, which affects its structure and function.
- Enzymes and antibodies are two types of protein that have 'active sites'. These are areas of the protein that have to be a specific shape for the protein to function properly.
Fats and oils
- Fats and oils are made up of two units: molecules called fatty acids and a molecule called glycerol.
- The number of and type fatty acids in the lipid determines its structure.
Test yourself on Larger Molecules
Which of these is not a unit that makes up fats and oils?