• 13 parts
  • Checked October 2026

Glucose Molecule Labeled

One glucose molecule, C₆H₁₂O₆, drawn as a ring, as a chain, and as its alpha and beta forms.

Glucose Molecule Labeled

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1 2 3 4 5 6 7 8 9 10 11 12 13
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Write the name of each numbered part.Answer key

  1. Carbon 1 (anomeric carbon)
  2. Carbon 2
  3. Carbon 3
  4. Carbon 4
  5. Carbon 5
  6. Carbon 6
  7. Ring oxygen
  8. Hydroxyl group (OH)
  9. Aldehyde group
  10. Hydroxyl on carbon 5
  11. CH₂OH group
  12. Alpha-glucose
  13. Beta-glucose

Drawn for this site on 2026-10-03 from plain geometry and the table derived from PubChem record 79025. 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 part is answered.

Next step Next: tell glucose from the other sugars

All 13 parts on the diagram

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The ring 8

  1. Carbon 1 (anomeric carbon) It sits beside the ring oxygen, at the right corner. In the chain it is the carbon of the aldehyde group.
  2. Carbon 2 The next carbon after carbon 1. Its hydroxyl group points down here and sits on the right of the chain.
  3. Carbon 3 Its hydroxyl group points up, into the ring drawing. On the chain that group is written on the left.
  4. Carbon 4 The left corner, opposite carbon 1. Its hydroxyl group points down.
  5. Carbon 5 The last carbon in the ring. It is bonded to the ring oxygen and carries carbon 6.
  6. Carbon 6 The only carbon outside the ring, above carbon 5. With its two hydrogen atoms and a hydroxyl group it is the CH₂OH group.
  7. Ring oxygen The one oxygen atom in the ring. It joins carbon 1 to carbon 5 and comes from the hydroxyl group of carbon 5.
  8. Hydroxyl group (OH) An oxygen atom bonded to a hydrogen atom. Glucose has five: one each on carbons 1, 2, 3, 4 and 6.

Chain, alpha and beta 5

  1. Aldehyde group Carbon 1 with a hydrogen atom and a double-bonded oxygen. It is why glucose is called an aldose.
  2. Hydroxyl on carbon 5 It bonds to carbon 1 to close the ring. Its oxygen becomes the ring oxygen. In D-glucose it is written on the right.
  3. CH₂OH group Carbon 6 with two hydrogen atoms and a hydroxyl group. It stays outside the ring when the chain closes.
  4. Alpha-glucose Its carbon 1 hydroxyl group points down. That is the opposite side from the CH₂OH group. About 36 percent of glucose in water is this form.
  5. Beta-glucose Its carbon 1 hydroxyl group points up. That is the same side as the CH₂OH group. About 64 percent of glucose in water is this form.

How this list was compiled: Every name and every direction checked on 2026-10-03 against the PubChem records of D-glucose, alpha-D-glucose, beta-D-glucose and the open-chain form (https://pubchem.ncbi.nlm.nih.gov/compound/ followed by 5793, 79025, 64689 and 107526); Wikipedia: Glucose and Monosaccharide, text only; the IUPAC Nomenclature of Carbohydrates (rules 2-Carb-2 and 2-Carb-6, on the Queen Mary University of London site); a general chemistry textbook chapter on LibreTexts (Cyclic Structures of Monosaccharides); the UCLA Illustrated Glossary of Organic Chemistry; the Purdue University general chemistry pages on carbohydrates; and Kimball's Biology Pages: Carbohydrates. Licence: own work

The drawing: Drawn for this site on 2026-10-03 from plain geometry and the table derived from PubChem record 79025; nothing traced. Licence: own work

How it works

Glucose is a sugar with six carbon atoms. In water almost all of it is a ring of five carbons and one oxygen. The ring is labeled atom by atom here, then opened into a chain.

Read the full guide

Number the carbons

Find the ring oxygen. The corner to its right is carbon 1. Count on around the ring, away from the oxygen, to carbon 5. Carbon 6 stands above the ring.

From chain to ring, alpha or beta

On the chain, carbon 1 is at the top, in the aldehyde group. The ring forms when the hydroxyl group on carbon 5 bonds to carbon 1. To tell alpha from beta, look only at carbon 1: its hydroxyl group points down in alpha-glucose, away from the CH₂OH group, and up in beta-glucose.

  • The thick edge of a ring is the side nearest you.
  • A group on the right of the chain points down in the ring.

Questions and answers

What is the chemical formula of glucose?

C₆H₁₂O₆: six carbon, twelve hydrogen and six oxygen atoms. All 24 are on the ring drawing. Five of the oxygen atoms are in hydroxyl groups and the sixth is the ring oxygen.

How are the carbons in glucose numbered?

From the aldehyde end of the chain. Carbon 1 carries the aldehyde group, and in the ring it sits next to the ring oxygen. Carbons 2 to 5 follow in order around the ring, and carbon 6 is outside it.

What is the difference between alpha and beta glucose?

Only the hydroxyl group on carbon 1: down in the alpha ring, up in the beta ring. In water the two change into each other, about 36 percent alpha to 64 percent beta. Starch is built from alpha rings, cellulose from beta.

Why is glucose drawn as a ring and as a chain?

Both are the same molecule. The chain closes into a ring when the hydroxyl group on carbon 5 bonds to carbon 1, and the ring can open again. In water nearly all glucose is in a ring form.

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