What is the Difference Between Respiration and Burning

The main difference between respiration and burning is that respiration is the breakdown of glucose to release energy, whereas burning is a chemical reaction between a fuel and an oxidant. Furthermore, respiration is a biochemical process occurring inside the cell while burning is a chemical process that is non-cellular. 

Respiration and burning are two processes which release energy stored in chemical bonds of compounds. During respiration, the sequential breakdown of chemical bonds slowly releases energy stored in ATP; however, during burning, the breakdown of all chemical bonds quickly releases energy in the form of heat. 

Key Areas Covered 

1. What is Respiration
     – Definition, Process, Importance
2. What is Burning
     – Definition, Process, Importance
3. What are the Similarities Between Respiration and Burning
     – Outline of Common Features
4. What is the Difference Between Respiration and Burning
     – Comparison of Key Differences

Key Terms 

ATP, Burning, Chemical Bonds, Combustion, Heat, Respiration

What is Respiration 

Respiration or cellular respiration is the set of chemical reactions that take place in a cell, converting biochemical energy into ATP. Although it is technically a type of combustion reaction, it occurs inside the cell, slowly releasing energy through a series of reactions. Furthermore, nutrients used in respiration include sugar, amino acids, and fatty acids. Meanwhile, the main form of respiration is aerobic respiration, which uses oxygen as the final electron acceptor. Basically, during aerobic respiration, glycolysis breaks down nutrients into pyruvate, which enters into mitochondria in order to undergo complete oxidization into carbon dioxide and water. Moreover, the energy released by the chemical reactions is stored in ATP through the substrate-level phosphorylation of NADH and FADH2.

Figure 1: Aerobic Respiration

Furthermore, in the absence of oxygen, respiration occurs in the form of fermentation. Here, pyruvate produced in glycolysis converts into waste products in two processes known as lactic fermentation and ethanol fermentation. Moreover, anaerobic respiration is the type of respiration in microorganisms whose final electron acceptor is inorganic acceptors such as sulfates or nitrates. 

What is Burning 

Burning or combustion is a high temperature, exothermic, redox reaction, occurring between a fuel and an oxidant. Usually, the oxidant is the atmospheric oxygen while the mixture of gaseous byproducts is called the smoke. Here, heat and light are the forms through which the energy of the reaction releases. Generally, the combustion of solid fuel such as wood and coal proceeds through endothermic pyrolysis, which produces gaseous fuels, undergoing combustion. Furthermore, the combustion of these gaseous fuels provides heat for producing more gaseous fuels.

Figure 2: Combustion of Methane

The combustion of an organic fuel in air is always an exothermic reaction. It is due to the higher bond strength of combustion products – carbon dioxide and water – when compared to the bond strength in the double bond of oxygen. Furthermore, complete combustion is the type of combustion which results in zero fuel at the end of the combustion reaction. In contrast, in incomplete combustion, unburned products such as carbon monoxide, hydrogen, even carbon in the form of ash may remain. 

Similarities Between Respiration and Burning  

• Respiration and burning are two processes of releasing energy stored in chemical bonds.  
• Both are catabolic reactions.  
• They are exothermic redox reactions, releasing heat.  
• Their reactants are complex chemical compounds, and they use oxygen to oxidize chemical bonds.  
• Moreover, their products are simple chemical compounds, mostly in the gaseous phase. 

Difference Between Respiration and Burning 

Definition 

Respiration refers to the biochemical process in which cells of an organism obtain energy by combining oxygen and glucose, releasing carbon dioxide, water, and ATP while burning refers to the chemical reaction, which occurs between a fuel and an oxidizing agent, producing energy in the form of heat and light. 

Natural or Initiated 

While respiration is a natural process, burning has to be initiated by applying heat. 

Continuity 

Furthermore, respiration is a continuous process, while burning is a discontinuous process. 

Type of Process 

Respiration is a type of biochemical process that occurs inside the cell while burning is a chemical process which is non-cellular. 

Enzymes 

Respiration is an enzymatic process while burning is a non-enzymatic process. 

Speed of Bond Breaking 

During respiration, chemical bonds slowly breakdown one by one while during burning, chemical bonds quickly breakdown all at once. 

Formation of Intermediates 

Moreover, respiration occurs through the formation of intermediates, while burning does not form intermediates. 

Steps 

While respiration is a multi-step process, burning is a single-step process. 

Speed of Releasing Energy 

Respiration releases energy slowly while burning releases energy quickly. 

Form of Energy Liberation 

The energy released during respiration is stored in ATP molecules, while a small amount of energy is liberated in the form of heat. In contrast, the energy is released in the form of heat and light during burning. 

Temperature Conditions 

Respiration occurs at physiological temperatures while burning occurs at high temperatures. 

Oxygen 

Oxygen serves as the terminal electron acceptor in respiration while burning directly uses oxygen in the process. 

Byproducts 

Carbon dioxide and water are the byproducts of respiration while carbon dioxide, sulfur dioxide, nitric oxide, oxygen, etc. are the byproducts of burning. 

Conclusion 

Respiration is a biochemical process that occurs inside cells with the help of enzymes. It also produces energy in the form of ATP by breaking down bonds, mainly in glucose. However, it is a slow process that proceeds through the formation of intermediates. On the other hand, burning is a non-cellular process which is chemical. Hear, heat has to be given to initiate the chemical reaction of burning. Generally, it is a type of rapid oxidation, which results in the release of energy quickly in the form of heat and light. Therefore, the main difference between respiration and burning is the type of bond breaking. 

References:

1. “Cellular Respiration – Definition, Equation and Steps.” Biology Dictionary, 14 June 2019, Available Here.
2. Helmenstine, Anne Marie. “Combustion: Definition and Equation.” ThoughtCo, ThoughtCo, 3 July 2019, Available Here.

Image Courtesy:

1. “CellRespiration” By RegisFrey – Own work (CC BY-SA 3.0) via Commons Wikimedia     
2. “Combustion reaction of methane” By JyntoRobert A. RohdeJacek FHJynto – Methane-3D-space-filling.svg Oxygen Molecule VdW.png Carbon-dioxide-3D-vdW.svgWater molecule 3D.svg (CC BY-SA 3.0) via Commons Wikimedia   

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