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Aerobic Vs Anaerobic Respiration: What's The Difference?

Published October 17, 2021

Aerobic respiration occurs in the presence of oxygen. The cells use oxygen to convert food into ATP, which is then used for cellular processes. Anaerobic respiration does not need oxygen and instead uses creatine phosphate as an energy source. This blog post will describe the difference between aerobic and anaerobic respiration so that you can better understand how your body works!

The human body is an amazing machine. In order to breathe, the lungs expand and contract in a rhythmic fashion. The expansion of the lung tissue creates a vacuum that pulls air into the lungs. This process is known as "aerobic respiration." An alternate form of respiration exists which does not require oxygen from the air we breathe in. This process is called "anaerobic respiration".

What is Aerobic Respiration?

Aerobic respiration is the process by which cells use oxygen to convert food into ATP, which is then used for cellular processes. Energy-rich molecules produced from food are combined with oxygen in order to generate energy. This process takes place inside the mitochondria of a cell and occurs over a longer period of time than anaerobic respiration.

In aerobic organisms, this form of respiration provides more efficient results as compared to other forms such as lactic acid fermentation or anaerobic glycolysis. Aerobic organisms tend to be better equipped at handling environmental changes that result from climate change. Whereas anaerobes cannot survive without high levels of atmospheric CO² because they rely on fermenting sugars to produce energy.

Aerobic respiration is a process that involves three major steps: glycolysis, the Krebs cycle, and the electron transport system (ETS). 

What is Anaerobic Respiration?

Anaerobic means "without air" or without oxygen. During anaerobic respiration, organisms use various molecules for metabolism instead of using oxygen as they do in aerobic respiration. These molecules are often organic compounds like carbohydrates but sometimes they can be other biologically relevant molecules such as amino acids which are used by some bacteria during fermentation reactions. This form of cellular respiration does not require molecular oxygen so it occurs inside cells where there isn't any available. It provides less efficient results than aerobic processes because ATP production is less efficient.

Anaerobic organisms are more commonly found in nature than aerobic ones because they can survive under conditions where there isn't any oxygen available. Whereas anaerobes cannot live without high levels of atmospheric CO². This could be due to the fact that many anaerobes do not have mitochondria. This means they lack oxidative phosphorylation enzymes needed for respiration and require fermenting sugars to produce energy instead. An example would be Methanosarcina barkeri whose species has been observed growing on acetate or carbon dioxide inside salt marsh sediments with no detectable level of molecular O² present nearby.

The process begins when pyruvate molecules produced from glycolysis enter into a separate pathway called fermentation. This creates compounds like lactic acid, ethanol, and carbon dioxide.

Differences Between Aerobic & Anaerobic Respiration

The DIfference in the survival of organisms

Anaerobic organisms are a lot more common in nature as compared to their aerobics counterparts due to the fact that they can survive under conditions where there isn't any available oxygen.

The process of obtaining energy through cellular respiration is the same in both aerobic and anaerobic organisms, but they are different because oxygen plays a role in some processes whereas it does not play any role at all during others. This results in weak ATP production as compared to when it takes place inside cells where O² is available. Therefore, anaerobic organisms are more likely to be seen in nature compared to aerobic ones due to their increased ability to survive.

The difference in the level of organisms

Another key difference is the fact that higher organisms have aerobic respiration whereas in lower organisms anaerobic respiration occurs.

In higher organisms, aerobic processes take place when cells generate energy from the oxidation of organic molecules which is a process that releases large amounts of O² as a byproduct during cellular metabolism. 

Lower organisms such as bacteria and archaea rely on fermenting sugars to produce energy through anaerobic respiration which is a process that does not require O² to take place.

The difference in exchange of gases

Aerobic organisms exchange gases through diffusion whereas anaerobic organisms use a process called active transport.

In aerobic processes, gas exchanges take place as O² enters into the cells and CO² exits from them. This process is called gas exchange. Anaerobes do not exchange gases because they do not require O² to take place.

Comparison Chart: Aerobic Vs Anaerobic Respiration

Energy producedMoreLess
Exchange of gasesYesNo
Organism survivalLessMore
Level of organismHigherLower

Similarities between Aerobic & Anaerobic respiration

Both aerobic and anaerobic organisms require energy to survive. They both processes generate ATP which is the energy currency of cells. Cell extracts are broken down into smaller molecules to produce energy in order for organisms to survive through cellular respiration. Whether this takes place aerobically or anaerobically ultimately depends on environmental conditions and species type.


Which is more effective?

Aerobic respiration produces more ATP compared to anaerobic processes which is why they are considered to be the most effective.

What is an example of anaerobic respiration?

Fermentation is an example of anaerobic respiration which produces a lot less energy as compared to aerobic processes.

What is an example of aerobic respiration?

In humans, aerobic respiration takes place in the cellular organelles called mitochondria which is a specialized structure that contains an electron transport chain. This transfers electrons from NADH or FADH² to O², to produce ATP through oxidative phosphorylation.


To conclude, aerobic and anaerobic processes are different from each other because one requires the presence of oxygen whereas the other does not. We hope that this blog will help you understand these processes better than before so that when it comes to your next biology test or just a conversation with friends, you can be sure of what is being said.


Feel free to comment and discuss about the article in the comment space below if you have any information or remarks to add. If you think we made a mistake, you can also report it there.

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About the Author: Tom Vincent

Tom Vincent graduated with a bachelor's degree in economics and social studies. He then started his higher education at the University of François Rabelais in Tours with a DUT Information Communication. To expand his knowledge, he also followed a professional degree in e-commerce and digital marketing at the Lumière University of Lyon. On this project, he is in charge of articles covering language, industry and social.
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