Cellular respiration is an important biological process that takes place within the cells of all living creatures. The primary function of cellular respiration is the conversion of energy from food into energy that can be used by cells to perform diverse functions, including development, reproduction and maintenance. In this process sugar (a straightforward sugar) transforms into energy by the use of ADP (adenosine triphosphate). This energy is then utilized by cells to perform different metabolic processes.

There are two primary processes of cell respiration: glycolysis and cell respiration. This article will concentrate specifically on chemical processes that take place in cellular respiration and the way they contribute to producing ATP.

Cellular respiration is a process where cells convert the energy of food to create. The process is carried out in mitochondria which are the specialized organelles within eukaryotic cells. The primary function of cell respiration is to produce ATP which is the principal source of energy utilized by cells in order to fulfill their duties.

The Chemical Reactions of Cellular Respiration

The chemical reactions in the cellular respiration process can be classified into three primary phases: glycolysis, citric acid cycle and electron transportation chain.

Glycolysis is the initial stage of cell respiration that is carried out in the cells of the cytoplasm. At this point the glucose is transformed into two pyruvate molecules. The reaction is catalyzed by various enzymes, and requires the contribution of two ATP molecules.

Glucose + 2 ADP + 2 NAD+ – 2 Pyruvate + 2 ATP + 2 NADH
In this process it converts glucose into pyruvate. This is then transported to the mitochondria. Both ATP molecules are produced through phosphorylation of the substrate, where the energy produced in the process is used to add a phosphate phosphate group to ADP and create ATP.

The Citric Acid Cycle
Citric acid, commonly referred to by”the Krebs cycle or tricarboxylic acid cycling is the second stage of cell respiration. This phase occurs in mitochondria and is characterized by the oxidation of Pyruvate, which results in the production of ATP as well as other by-products.

Pyruvate + CoA + NAD+ – Acetyl-CoA + NADH + CO2
Through this process, pyruvate transformed into acetyl-CoA. It can then be used to make ATP as well as other byproducts. The energy generated during this reaction is utilized to create ATP by phosphorylation at the substrate level.

Acetyl-CoA + 3 NAD+ + FAD + GDP + Pi – Citrate + CO2 + 2 NADH + FADH2 + GTP
When you go through the citric acid cycle citrate is created, which transforms into ATP and various by-products. The energy produced by this reaction is used to produce ATP via substrate-level phosphorylation.

The Electron Transport Chain

It is also the third and last stage of the process of respiration in cells. This process occurs within the inner membrane of mitochondria, and is the process of transferring electrons between NADH and FADH2 back to oxygen. The transfer creates the proton gradient that is utilized to create ATP by the process of oxidative or phosphorylation.

NADH + H+ – NAD+ + H2O

Reaction, NADH contributes electrons in the electron transport chain that results in the creation the formation of NAD+. The energy produced by this process is utilized to create an electron gradient that is then used to make ATP.

FADH2 + H+ – FAD + H2O
This reaction FADH2 is also able to donate electrons into the transport chain which leads to the formation of FAD. The energy generated in this reaction can be utilized to create an electron gradient.

The proton gradient produced via the electron transport chain can be used create ATP by the process of oxidative phosphorylation. This happens within the ATP synthase complex that is located inside the membrane inside mitochondria. The proton gradient is the driving force behind this process of rotation. ATP synthase complex. This causes the formation of ATP.

ADP + Pi – ATP
In this process, ADP is converted into ATP by the process of oxidative the process of phosphorylation. It requires addition of energy via the proton gradient that is created through the chain of electron transportation.

The Overall Reaction of Cellular Respiration
The total reaction of cellular respiration could be described in the following manner:

Glucose + 6O2 – 6CO2 + 6H2O + ATP
In this process the glucose is transformed into H2O and CO2, which are organic waste products from cell respiration. The energy produced by this process is used to make ATP which is the primary energy source utilized by cells.


Cellular respiration is a vital biological process that happens throughout all living organisms. It involves the conversion of energy from food into energy that cells use to perform various tasks. The chemical reactions that occur during cell respiration can be categorized into three major stages that are glycolysis and the citric acid cycle as well as the chain of electron transportation. These reactions result in creation of ATP which is the main source of energy utilized by cells. Knowing the reactions involved in the cellular respiration process is crucial to understanding the biological basis of living organisms.