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Cellular Respiration vs. Fermentation: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on December 16, 2023
Cellular respiration is a process where cells convert nutrients into energy using oxygen. Fermentation is an anaerobic process that converts sugar to acids, gases, or alcohol.

Key Differences

Cellular respiration is a complex process where cells convert glucose and oxygen into energy, water, and carbon dioxide. In contrast, fermentation is a simpler, anaerobic process that breaks down glucose without oxygen, producing less energy.
Cellular respiration occurs in the mitochondria of cells and involves several steps, including glycolysis, the Krebs cycle, and electron transport chain. Fermentation, however, takes place in the cytoplasm and typically includes just glycolysis, leading to the production of lactic acid or alcohol.
Cellular respiration is more efficient than fermentation, generating up to 38 ATP molecules per glucose molecule, whereas fermentation produces only about 2 ATPs.
Oxygen is essential for cellular respiration; it serves as the final electron acceptor in the electron transport chain. Fermentation occurs in the absence of oxygen, making it crucial for organisms in oxygen-depleted environments.
Cellular respiration results in the complete oxidation of glucose, leading to carbon dioxide and water as waste products. In fermentation, incomplete oxidation of glucose produces ethanol or lactic acid as by-products.

Comparison Chart

Oxygen Requirement

Requires oxygen
Occurs without oxygen

Energy Efficiency

High (up to 38 ATP per glucose)
Low (about 2 ATP per glucose)

Location in Cell


Process Complexity

Involves multiple steps
Relatively simple process


Carbon dioxide and water
Ethanol, lactic acid, or other fermentation products

Cellular Respiration and Fermentation Definitions

Cellular Respiration

The process involving glycolysis, the Krebs cycle, and the electron transport chain.
Cellular respiration in yeast cells is crucial for their survival and growth.


The anaerobic process of breaking down glucose to produce energy.
Yeast fermentation produces alcohol in brewing.

Cellular Respiration

The process of breaking down glucose with oxygen to produce energy.
Cellular respiration in human cells provides energy for bodily functions.


A metabolic process that converts sugar to acids, gases, or alcohol.
Lactic acid fermentation occurs in muscles during intense exercise.

Cellular Respiration

A series of reactions using oxygen to generate ATP from organic compounds.
In cellular respiration, mitochondria play a key role in energy production.


A biological process that produces ethanol or lactic acid in anaerobic conditions.
Fermentation is used in making bread rise.

Cellular Respiration

A metabolic pathway that converts food to ATP, water, and carbon dioxide.
Plants undergo cellular respiration at night, converting sugars into energy.


The enzymatic breakdown of carbohydrates without oxygen.
Fermentation in bacteria results in the production of yogurt.

Cellular Respiration

The aerobic breakdown of nutrients to release energy.
Cellular respiration is essential for muscle cells during exercise.


Any of a group of chemical reactions induced by microorganisms or enzymes that split complex organic compounds into relatively simple substances, especially the anaerobic conversion of sugar to carbon dioxide and alcohol by yeast.


Unrest; agitation.


(biochemistry) Any of many anaerobic biochemical reactions in which an enzyme (or several enzymes produced by a microorganism) catalyses the conversion of one substance into another; especially the conversion (using yeast) of sugars to alcohol or acetic acid with the evolution of carbon dioxide


A state of agitation or excitement; a ferment.


The process of undergoing an effervescent change, as by the action of yeast;


A state of agitation or excitement, as of the intellect or the feelings.
It puts the soul to fermentation and activity.
A univesal fermentation of human thought and faith.


A process in which an agent causes an organic substance to break down into simpler substances; especially, the anaerobic breakdown of sugar into alcohol


A state of agitation or turbulent change or development;
The political ferment produced a new leadership
Social unrest


A chemical phenomenon in which an organic molecule splits into simpler substances


The process used by cells to extract energy from carbohydrates when oxygen is scarce.
Fermentation in yeast is vital for wine production.


Does fermentation require oxygen?

No, fermentation is an anaerobic process and occurs without oxygen.

What types of cells use fermentation?

Many types, including yeast and muscle cells, use fermentation.

What is the main purpose of cellular respiration?

To convert glucose and oxygen into ATP, water, and carbon dioxide for energy.

What are the end products of cellular respiration?

The end products are ATP, water, and carbon dioxide.

What is a common use of fermentation in food?

Fermentation is used in bread-making, brewing, and yogurt production.

Can fermentation occur in aerobic conditions?

Typically, it occurs under anaerobic conditions.

How efficient is cellular respiration compared to fermentation?

Cellular respiration is more efficient, generating more ATP than fermentation.

Can fermentation occur in human cells?

Yes, lactic acid fermentation occurs in muscles during anaerobic conditions.

What is a key difference in by-products between the two processes?

Cellular respiration produces CO2 and water; fermentation produces ethanol or lactic acid.

Can plants perform fermentation?

Yes, some plants can ferment under anaerobic conditions.

Is oxygen a by-product of cellular respiration?

No, oxygen is a reactant, not a by-product.

How do muscle cells use fermentation?

Muscle cells use lactic acid fermentation when oxygen is low during intense exercise.

What is the energy yield of fermentation?

About 2 ATP molecules per glucose molecule.

What happens to the pyruvate in fermentation?

It is converted into ethanol or lactic acid, depending on the organism.

Where does cellular respiration occur in the cell?

It occurs in the mitochondria of eukaryotic cells.

Is fermentation a form of cellular respiration?

No, fermentation is a separate process from cellular respiration.

Why is cellular respiration important for living organisms?

It provides the necessary energy for cellular functions.

What role does glycolysis play in both processes?

Glycolysis is the first step in both cellular respiration and fermentation.

Can cellular respiration occur without oxygen?

No, it requires oxygen to be fully efficient.

Is ATP produced in fermentation?

Yes, but less than in cellular respiration.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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