Monosaccharides are single‑unit (simple) sugars such as glucose , fructose , galactose , ribose , and xylose.

What counts as a monosaccharide?

A monosaccharide is:

  • One sugar unit that cannot be hydrolyzed to a simpler sugar.
  • Generally fitting the formula Cn(H2O)n\text{C}_n(\text{H}_2\text{O})_nCn​(H2​O)n​ for many common examples (like glucose: C₆H₁₂O₆).
  • Typically water‑soluble, sweet, and serving as a primary energy source in cells.

Common examples

Common biologically important monosaccharides include:

  • Glucose (blood sugar)
  • Fructose (fruit sugar)
  • Galactose
  • Ribose (in RNA)
  • Deoxyribose (in DNA)
  • Mannose
  • Xylose and arabinose

If your original question listed options such as “glucose, fructose, sucrose, starch,” then:

  • Glucose → monosaccharide
  • Fructose → monosaccharide
  • Sucrose → disaccharide (glucose + fructose), not a monosaccharide
  • Starch → polysaccharide, not a monosaccharide

Mini recap (for exams)

When asked “which of the following are monosaccharides?”:

  1. Pick single‑word simple sugars like glucose, fructose, galactose, ribose, mannose.
  1. Exclude disaccharides (sucrose, lactose, maltose) and polysaccharides (starch, glycogen, cellulose).

Information gathered from public forums or data available on the internet and portrayed here.