Question

In detail, describe a decarboxylation-redox reaction that occurs during glucose metabolism.

Answer 1

Redox reaction - It is also known as oxidation-reduction reaction. This type of chemical reaction involves a transfer of electrons between two species. A redox reaction is a chemical reaction in which the oxidation number of a ion, atom or molecule changes by gain (reduction) or loss (oxidation) of an electron.

Decarboxylation reaction - It is a chemical reaction in which a carboxyl group is removed and carbon dioxide is released. Usually, it is a reaction of carboxylic acids, removing a C-atom from a C-chain.

Aerobic respiration - It is the main type of cellular respiration in humans. In this process energy is released with CO2 and H2O as byproducts on metabolising glucose and O2.

36 molecules of ATP in the form of energy are synthesized after complete aerobic oxidation of glucose:

C6H12O6 + 6O2 + 36Pi2- + 36 ADP3- + 36H+  → 6CO2 + 36ATP4- + 42H2O

Oxidation decarboxylation and reduction - pyruvic acid in glycolysis.

• Pyruvate is oxidised by removal of H2 and
• Pyruvate is decarboxylated by removal of CO2 to produce acetyl CoA. Citric acid cylce is initiated by acetyl CoA.
• The H2 that is released reduces NAD to NADH2.

Glycolysis is the initial stage of glucose metabolism. It takes place in the cytosol and doesn't involves molecular O2. Glycolysis produces a small amount of ATP and the 3-C compound pyruvic acid (pyruvate). Pyruvate formed in glycolysis is transported into the mitochondria and oxidized by oxygen to CO2. Pyruvate oxidation in the mitochondria generates the bulk of the ATP which is produced during the conversion of glucose to CO2.