• 16 boxes
  • Checked October 2026

Fermentation Diagram

Two charts from the same start: pyruvate to lactate, and pyruvate to ethanol.

Fermentation Diagram

Name Date

Tap any box to read, rename or leave it out

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
More options

Write the name of each numbered box.Answer key

  1. Glucose
  2. Glycolysis
  3. Pyruvate
  4. ATP
  5. NADH
  6. NAD⁺
  7. Lactate dehydrogenase
  8. Lactate
  9. Pyruvate
  10. Pyruvate decarboxylase
  11. Carbon dioxide
  12. Acetaldehyde
  13. Alcohol dehydrogenase
  14. NADH
  15. NAD⁺
  16. Ethanol

Drawn for this site on 2026-10-01 from plain geometry. 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 box is answered.

Next step Next: cellular respiration, the path with oxygen

All 16 boxes on the diagram

Show the list

Lactic acid fermentation 8

  1. Glucose The sugar that is broken down. Fermentation gets a little of its energy out without oxygen.
  2. Glycolysis It splits one glucose into two pyruvate. Two ATP and two NADH are made on the way.
  3. Pyruvate What glycolysis leaves: two molecules of three carbons.
  4. ATP The cell's gain: two ATP for each glucose. All of it comes from glycolysis.
  5. NADH It carries electrons taken from the sugar in glycolysis. The enzyme below takes them off again.
  6. NAD⁺ It is made again from NADH. Glycolysis needs it to keep going.
  7. Lactate dehydrogenase The enzyme that turns pyruvate into lactate. It uses NADH and gives back NAD⁺.
  8. Lactate The end product of this path. Lactic acid is its acid form.

Alcoholic fermentation 8

  1. Pyruvate The same pyruvate that glycolysis made. Here it takes the other path.
  2. Pyruvate decarboxylase The enzyme that takes carbon dioxide off pyruvate. What is left is acetaldehyde.
  3. Carbon dioxide The gas given off. One carbon leaves each pyruvate this way.
  4. Acetaldehyde What is left of pyruvate: two carbons. It takes the electrons that NADH carries.
  5. Alcohol dehydrogenase The enzyme that turns acetaldehyde into ethanol. It uses NADH and gives back NAD⁺.
  6. NADH It arrives from glycolysis with electrons. The enzyme above passes them to acetaldehyde.
  7. NAD⁺ It is made again here too. It goes back to glycolysis.
  8. Ethanol The end product of this path. It is an alcohol with two carbons.

How this list was compiled: Every name, step and detail checked on 2026-10-01 in at least two places, for facts only and with nothing copied: Wikipedia, text only (Fermentation, Lactic acid fermentation, Ethanol fermentation); Kimball's Biology Pages (Glycolysis); two biochemistry textbooks read on archive.org by full-text search (G. Gottschalk, Bacterial Metabolism, 1986; J. O'Neale Roach, Metabolism and Nutrition, 2003); and a review article read through Europe PMC (PMC3719019). Licence: own work

The drawing: Drawn for this site on 2026-10-01 from plain geometry; nothing traced. Licence: own work

How it works

Label the essential steps of fermentation on two charts. The first follows glucose through glycolysis to lactate. The second starts at pyruvate and ends at ethanol and carbon dioxide.

Read the full guide

Lactic acid fermentation

Glycolysis splits glucose into two pyruvate and gains two ATP. It also turns NAD⁺ into NADH. Lactate dehydrogenase then passes the electrons of NADH to pyruvate, which becomes lactate, and NAD⁺ is made again for glycolysis. Muscle cells do this.

Alcoholic fermentation

Yeast starts the same way. Pyruvate decarboxylase takes carbon dioxide off pyruvate and leaves acetaldehyde. Alcohol dehydrogenase turns acetaldehyde into ethanol, and here too NADH becomes NAD⁺. The dashed arrows lead from glycolysis on the first chart and back to it.

  • Rounded boxes are molecules, the square-cornered box is the stage, and boxes with cut corners are enzymes.
  • The dots beside a molecule count its carbons.

Questions and answers

What are the steps of fermentation?

Glycolysis comes first: glucose is split into two pyruvate, with two ATP and two NADH made. Then pyruvate is turned into lactate, or into ethanol and carbon dioxide, and NADH is turned back into NAD⁺.

What is the difference between lactic acid and alcoholic fermentation?

In lactic acid fermentation pyruvate is turned straight into lactate. In alcoholic fermentation pyruvate first loses carbon dioxide and becomes acetaldehyde, which is then turned into ethanol.

What is the purpose of fermentation?

To make NAD⁺ again. Glycolysis needs NAD⁺ to keep going, and fermentation gets it back by passing the electrons of NADH to pyruvate or to acetaldehyde.

How much ATP does fermentation make?

By these two paths, two ATP for each glucose, all of it from glycolysis. The steps after pyruvate make no ATP.

More quizzes

Show 6 more

Browse Science Quizzes