Question

What is a redox reaction?

What is the importance of a coenzyme like NAD+?

What is the role of NAD+ as an electron carrier?

Answer 1

Question-1: What is a redox reaction?

A reaction in which both oxidarion involving loss of electron and also reduction involving gain of electrons is defined as redox reaction. This reaction is involving transfer of electrons.

Example of redox reaction:

In a few organisms in order to metabolize gamma –amino butyric acid enzyme that is succinate-semialdehyde dehydrogenase is potentially converts succinate semialdehyde into succinate using a cofacotor that is nicotine amide diamide (NAD+) and finally leading to production of NADH + 2 H+.

In case of citric acid cycle, alpha ketoglutarate is going to be converted to succinic semi aldehyde and later this semialdhyde component is going to be converted to succinate by redox reaction and this reaction is a reversible reaction.

succinate semialdehyde + NAD⁺ + H₂O <--------------> succinate + NADH + 2 H⁺

Redox reactions occur during electron transport systems, the energy released is utilized to generate ATP.

Question-2: What is the importance of a coenzyme like NAD+?

Nicotinamide adenine dinucleotide (NAD+): It is an electron carrier and potentially involved in redox reactions. It is existing in both oxidized form as NADH and reduced form NAD⁺ . In oxidised from (NADH) it produces 3 ATP energy molecules duering oxidative phosphorylation in electron transport chain of mitochondria.

Example of NAD+ involving reaction:

Citric acid cycle is the connecting step between the glycolysis and the electron transport chain. The pyruvate generated by the glycolysis is converted into acetyl-CoA that enters into the citric acid cycle. Conversion of pyruvic acid into acetyl CoA is in the mitochondria. The high energy compounds generated by citric acid cycle enter the electron transport chain.

Pyruvate + NAD+ --------------------> Acetyl CoA (enters the citric acid cycle) + CO2 + NADH + H+          + Coenzyme A

Question-3: What is the role of NAD+ as an electron carrier?

Answer:

It is existing in both oxidized form as NADH and reduced form NAD⁺ . In oxidised from (NADH) it produces 3 ATP energy molecules duering oxidative phosphorylation in electron transport chain of mitochondria.