NADH and NAD⁺ are not the same

NAD⁺ (Nicotinamide Adenine Dinucleotide)

• What it is: NAD⁺ is the oxidized form of the molecule. It acts as an electron acceptor in many metabolic reactions.

• Role in the cell: It accepts electrons (and a hydrogen ion, H⁺) from metabolic reactions, becoming NADH in the process. By accepting these electrons, NAD⁺ helps drive important processes like glycolysis, Krebs cycle, and oxidative phosphorylation.

Equation:

NAD⁺ + 2 electrons + H⁺ → NADH

NADH (Reduced Nicotinamide Adenine Dinucleotide)

• What it is: NADH is the reduced form of NAD⁺, meaning it carries electrons and hydrogen. After gaining these, NAD⁺ becomes NADH.

• Role in the cell: NADH is a carrier of high-energy electrons. It donates these electrons to the electron transport chain (ETC) in the mitochondria, which is essential for the production of ATP. Once it donates its electrons in the ETC, it becomes NAD⁺ again and can participate in new rounds of electron transport.

Equation:

NADH → NAD⁺ + 2 electrons + H⁺

Key Differences:

• NAD⁺ is the oxidized form and acts as an electron acceptor.

• NADH is the reduced form and acts as an electron carrier or donor, helping to produce ATP.

In summary, the two forms are part of a cycle: NAD⁺ accepts electrons (becomes NADH), and NADH donates electrons (becomes NAD⁺). This continuous cycle is essential for energy production in cells.

To simplify it even more:

NAD⁺

• Think of NAD⁺ as an empty shuttle.

• Its job is to pick up electrons from processes like breaking down food (glucose).

• Once it picks up electrons, it becomes NADH.

NADH

• Now, NADH is a full shuttle.

• Its job is to drop off electrons at a place in the cell called the electron transport chain (in the mitochondria), where these electrons help make energy (ATP).

• After dropping off the electrons, NADH turns back into NAD⁺ and is ready to pick up more electrons.

The cycle:

• NAD⁺ (empty shuttle) picks up electrons and turns into NADH (full shuttle).

• NADH drops off the electrons to help make energy and turns back into NAD⁺.

This cycle keeps going to help the cell make energy continuously!