Carbohydrate monomers
Monosaccharides are simple sugars that act as the monomers used to construct larger carbohydrates. Carbohydrates contain carbon, hydrogen and oxygen.
Common monosaccharides include glucose, galactose and fructose. Monosaccharides can be joined in condensation reactions to produce disaccharides and polysaccharides.
Glucose has the molecular formula . Galactose and fructose have the same molecular formula as glucose but different arrangements of their atoms, so their structural formulae differ.
| Monosaccharide | Key point |
|---|---|
| Glucose | A common monosaccharide used as a respiratory substrate and as a building unit for larger carbohydrates. |
| Galactose | Has the molecular formula but a different structural formula from glucose. |
| Fructose | Has the molecular formula but a different structural formula from glucose. |
Exam Tip: If asked for examples of monosaccharides, use glucose, galactose and fructose. Maltose, sucrose and lactose are disaccharides, not monosaccharides.