Question

Which of the following statements regarding the chemical grooming of pyruvate is false?

A) Two molecules of pyruvate are each converted into two-carbon molecules joined to a coenzyme A molecule.
B) Each pyruvate loses a carbon atom, which is released as CO₂.
C) Two pyruvate molecules together contain less chemical energy than was found in the original glucose molecule.
D) The pyruvate molecules are oxidized and two NAD+ are reduced.
E) Each pyruvate molecule has a CO₂ added and then joins with an NADH.

Answer 1

The false statement about the chemical grooming of pyruvate is that each pyruvate molecule has a CO₂ added and then joins with an NADH. Pyruvate actually loses a CO₂ during its conversion to acetyl CoA, and in this process, NAD+ is reduced to NADH.

Step-by-step explanation:

The statement regarding the chemical grooming of pyruvate that is false is: E) Each pyruvate molecule has a CO₂ added and then joins with an NADH. In fact, the correct process involves each pyruvate molecule losing a carbon atom, which is released as CO₂, rather than gaining one.

During the conversion of pyruvate to acetyl coenzyme A (acetyl CoA), the three-carbon pyruvate molecule undergoes an oxidative decarboxylation reaction. This means that one carbon atom is removed from the pyruvate, releasing it as carbon dioxide (CO₂), while the remaining two carbons form an acetyl group that is attached to coenzyme A. Concurrently, NAD+ is reduced to NADH as it accepts electrons released during the oxidative process.