When you learn that respiration and combustion are “chemically” the same thing, the distinction between the two becomes immediately clear to you. However, there are specific mechanisms and enzymes in our bodies that manage this process of releasing energy, ensuring that our food does not spontaneously combust, as happens with rocket fuel or vehicle gasoline, for example.

Definition of Respiration

It is through the process of respiration that all living organisms obtain the energy they require to survive. Cellular respiration is the term used to describe this process because it takes place within cells. In most cases, two gases are exchanged: oxygen and carbon dioxide, respectively. In the process of respiration, the cells consume oxygen and exhale carbon dioxide. Aerobic respiration is the term used to describe this particular style of breathing. It is possible to breathe without the usage of oxygen under some circumstances. This mechanism is referred to as anaerobic respiration in the scientific community. Fermentation is another term for this process.

Definition of Combustion

It is a chemical reaction that creates heat and light in the form of flame, and it is typically accompanied by the release of oxygen into the atmosphere. There is a rapid rate at which the reactants combine, partly due to the nature of the chemical reaction, and partly due to the fact that more energy is generated than can be released into the surrounding medium, resulting in the temperature of the reactants being raised to even higher temperatures in order to accelerate the reaction even further.

People have been observing and thinking about combustion, fire, and flames since the beginning of recorded history. Every society has come up with its own theory for why this is happening. The Greeks described combustion in terms of philosophical conceptions, one of which was that all combustible bodies included an “inflammable essence,” which was activated when the body was burned in order to react with air.

Differences Between Respiration and Combustion

Respiration

Combustion

  • It is the process through which nutrients are transformed into usable energy in a cell that is referred to as cellular respiration

  • Combustion is a non-cellular and uncontrolled process in which energy is released in a single step as a result of the burning of various substances

  • It is a biological process in which energy is released in stages as the chemical bonds break one by one in the presence of oxygen

  • It is a physicochemical process in which chemical stages occur simultaneously rather than step-by-step as opposed to other processes

  • Approximately 50% of the energy is released in the form of heat

  • The majority of the energy is released as heat

  • It only does this in a very small number of instances

  • It also generates light, and the temperature rises to extremely high levels as a result of this process

  • It does not result in an increase in temperature, and most of the energy is trapped in the form of ATP molecules

  • This procedure does not entail the production of ATP

  • As a result of the reaction between oxygen and coenzymes, oxidation happens towards the end of the process known as respiration

  • In this case, the substrate is directly oxidised in combustion, with no intermediates being produced

  • It is carried out with the assistance of numerous enzymes, with one enzyme required for each stage or reaction in the process

  • It is a burning process that does not necessitate the use of an enzyme

Conclusion

Understanding the differences between respiration and combustion is important; nevertheless, it is the commonalities that cause us to compare the two and discuss the differences that are as important. Let’s take a look around!

  • Both combustion and respiration are characterised by the burning of their respective substrates

  • Both of these processes result in the oxidation of the chemical involved (in presence of oxygen)

  • Both of these actions free up energy

  • Both produce by-products in the form of oxides as a result of their processes