Questions: Examine the biochemical reaction below: CH3CH2OH + NAD+ ↔ CH3CHO + NADH + H+ Which of the following molecules is reduced in the aforesaid reaction? EtOH NAD+ NADH Acetaldehyde

Examine the biochemical reaction below:
CH3CH2OH + NAD+ ↔ CH3CHO + NADH + H+
Which of the following molecules is reduced in the aforesaid reaction?
EtOH
NAD+
NADH
Acetaldehyde

Transcript text: Examine the biochemical reaction below: \[ \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}+\mathrm{NAD}^{+} \leftrightarrow \mathrm{CH}_{3} \mathrm{CHO}+\mathrm{NADH}+\mathrm{H}^{+} \] Which of the following molecules is reduced in the aforesaid reaction? EtOH $\mathrm{NAD}^{+}$ NADH Acetaldehyde Submit Request Answer

Solution

Solution Steps

Step 1: Identify the Redox Reaction Components

In a redox reaction, one species is oxidized (loses electrons) and another is reduced (gains electrons). In the given reaction:

\[ \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}+\mathrm{NAD}^{+} \leftrightarrow \mathrm{CH}_{3} \mathrm{CHO}+\mathrm{NADH}+\mathrm{H}^{+} \]

we need to identify which molecule is gaining electrons (reduced) and which is losing electrons (oxidized).

Step 2: Determine the Oxidation and Reduction

Ethanol ($\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}$) is oxidized to acetaldehyde ($\mathrm{CH}_{3} \mathrm{CHO}$). This involves the loss of hydrogen atoms (which are equivalent to losing electrons).
$\mathrm{NAD}^{+}$ is reduced to $\mathrm{NADH}$. This involves the gain of electrons (and a hydrogen ion).

Step 3: Identify the Reduced Molecule

The molecule that gains electrons in this reaction is $\mathrm{NAD}^{+}$, which is reduced to $\mathrm{NADH}$.