Cellular Respiration Is An Efficient And Widespread Catabolic Process

815 Words Oct 17th, 2016 4 Pages
Cellular respiration is an efficient and widespread catabolic process, which uses oxygen as a reactant to complete the breakdown of a variety of organic molecules.
In the process of cellular respiration, the sugar releases chemical-bond energy, which the cell stores in the chemical bonds of ATP.

The chemical equation for respiration is:
C6H12O6 + 6O2 6CO2 + 6H2O + (ATP)
Glucose + Oxygen Carbon Dioxide + Water
Glucose is oxidized, oxygen is reduced, and electrons loses potential energy.
The reactant molecules glucose & oxygen come apart, and their atoms regroup to form the products carbon dioxide and water. In the process, glucose releases chemical-bond energy, which the cell stores in the chemical bonds of ATP.

Respiration occurs in three metabolic stages: glycolysis, the Krebs cycle, and in the electron transport chain.

The first 2 stages are exergonic (or energy releasing). Glycolysis which begins within the cytoplasm initiates respiration by breaking down Glucose into two molecules of pyruvic acid. Each of the ten steps in glycolysis is catalyzed by a specific enzyme. These steps can be divided into two phases: an energy investment phase and an energy payoff phase. In the energy investment phase, ATP provides activation energy by phosphorylating glucose which requires 2 ATP per glucose. In the energy payoff phase, ATP is produced by substrate-level phosphorylation and NAD+ is reduced to NADH. Glycolysis occurs whether O2 is present or not universally…

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