Question

"When the apple slices were transferred to nitrogen, the following biochemical pathway took place: Pyruvic acid ---> Ethanol (CH3-CO-COOH) ---> (CH3-CH2-OH) Use this pathway to explain the part played by reduced NAD when the apple slices were transferred to nitrogen. (2)"

a) Reduced NAD is produced when pyruvic acid is converted to ethanol, providing energy to the apple.
b) Reduced NAD is consumed when pyruvic acid is converted to ethanol, releasing carbon dioxide.
c) Reduced NAD is a byproduct of the conversion of ethanol to pyruvic acid.
d) Reduced NAD plays no role in the pathway from pyruvic acid to ethanol.

Answer 1

Reduced NAD plays a key role in the pathway from pyruvic acid to ethanol when apple slices are transferred to nitrogen.

Step-by-step explanation:

When apple slices are transferred to nitrogen, the biochemical pathway that takes place involves the conversion of pyruvic acid to ethanol. In this pathway, reduced NAD (nicotinamide adenine dinucleotide) plays a crucial role. The conversion of pyruvic acid to ethanol results in the production of reduced NADH, which provides the necessary energy for the apple slices.

During this process, pyruvic acid is first converted to acetaldehyde, releasing carbon dioxide as a gas. Then, NADH donates its electrons to acetaldehyde, which is subsequently reduced to ethanol. This oxidation of NADH to NAD* allows the pathway to continue and produces ethanol from pyruvic acid