Monosaccharides and Disaccharides Diagram

Eight sugars drawn as rings: tell them apart by the ring and the groups on it.

Monosaccharides and Disaccharides Diagram

Name Date

Tap any sugar to read, rename or leave it out

1 2 3 4 5 6 7 8 9
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Write the name of each numbered sugar.Answer key

  1. Glucose
  2. Galactose
  3. Fructose
  4. Ribose
  5. Deoxyribose
  6. Sucrose
  7. Lactose
  8. Maltose
  9. Glycosidic bond

Drawn for this site on 2026-10-01 from plain geometry and a table derived from PubChem records. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a sugar is answered.

Next step Next: the four classes of macromolecules

All 9 sugars on the diagram

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Monosaccharides 5

  1. Glucose Its ring has five carbons and one oxygen. The formula is C₆H₁₂O₆.
  2. Galactose It differs from glucose at one carbon only. The OH on the left corner points the other way.
  3. Fructose Same formula as glucose, C₆H₁₂O₆, in a different arrangement. The ring has four carbons and one oxygen.
  4. Ribose The five-carbon sugar of RNA. Its formula is C₅H₁₀O₅.
  5. Deoxyribose The five-carbon sugar of DNA. It has one oxygen fewer than ribose: C₅H₁₀O₄.

Disaccharides and their bond 4

  1. Sucrose One glucose joined to one fructose. It is table sugar.
  2. Lactose One galactose joined to one glucose. It is the sugar of milk.
  3. Maltose Two glucose units joined together. It is also called malt sugar.
  4. Glycosidic bond The link between two sugar units, through one oxygen atom. Forming it releases a molecule of water.

How this list was compiled: Every ring checked on 2026-10-01 against the PubChem compound record of the sugar (https://pubchem.ncbi.nlm.nih.gov/compound/ followed by 79025, 439357, 439709, 447347, 439576, 5988, 6134 and 6255): a script reads which way each group points from the record and the drawing is made from that table. Names and which units join from Wikipedia: Monosaccharide, Disaccharide, Glucose, Galactose, Fructose, Ribose, Deoxyribose, text only, and Alberts and others, Molecular Biology of the Cell, 4th edition, chapter 2 (NCBI Bookshelf NBK26883, archived copy). Licence: own work

The drawing: Drawn for this site on 2026-10-01 from plain geometry and a table derived from PubChem records; nothing traced. Licence: own work

How it works

A monosaccharide is a single sugar unit and a disaccharide is two units joined. The first sheet shows five single sugars as rings; the second shows three double sugars and the bond between their rings.

Read the full guide

How to tell the rings apart

Count the sides first. Glucose and galactose are six-sided rings; they differ only at the left corner, where the OH points down in glucose and up in galactose. Fructose, ribose and deoxyribose are five-sided. Fructose has two CH₂OH groups. Ribose has an OH under both bottom corners, and deoxyribose is missing one of them. For a disaccharide, name each ring: sucrose is glucose and fructose, lactose is galactose and glucose, and maltose is two glucose units. The oxygen bridge between two rings is a glycosidic bond.

  • A book may draw the right-hand OH the other way up: the same sugar in its other ring form.
  • Hydrogen atoms are left off the rings.

Questions and answers

How do I label the following monosaccharides on a worksheet?

Look at the ring. Six sides with the left OH down is glucose; with the left OH up, galactose. Five sides with two CH₂OH groups is fructose. Five sides with one CH₂OH is ribose, or deoxyribose if a bottom corner has no OH.

How do I label the following disaccharides?

Name the two rings. A six-sided ring joined to a five-sided ring is sucrose. Two six-sided rings are lactose if the left one is galactose, and maltose if both are glucose.

What is the difference between a monosaccharide and a disaccharide?

A monosaccharide is one sugar unit, such as glucose. A disaccharide is two monosaccharides joined by a glycosidic bond. A molecule of water is released when the bond forms.

How is deoxyribose different from ribose?

Deoxyribose has one oxygen atom fewer. Ribose is C₅H₁₀O₅ and deoxyribose is C₅H₁₀O₄: one ring carbon carries no OH group. Ribose is the sugar of RNA and deoxyribose the sugar of DNA.

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