What would happen to the citric acid cycle if NADH and FADH 2 were not reoxidized?

Hi, everybody. Let's take a look at this next problem. It says true or false. The citric acid cycle can still proceed even if N A DH and Fa DH two do not undergo re oxidation. So what does this mean? Well, N A DH and fa DH two are the reduced forms of these molecules. And in the crib cycle or in the citric acid cycle, you need their oxidized forms. N AD plus and F ad. So our oxidized forms are needed to act as electron acceptors in four steps of the citric acid cycle. So once they accept those electrons, they become N A DH and FA DH two. So these molecules are not consumed by the citric acid cycle, but cycle back and forth, they accept electrons become reduced, then get re oxidized to go back into the cycle if these do not get re oxidized. So if they do not undergo re oxidation, the supply of N A DH D plus and F AD will not be renewed and therefore get depleted. So if our oxidized forms are depleted, arrow there, the citric acid cycle cannot proceed. It needs those electron electron receptors and there's four steps for the reactions to take place. So as N A plus and F ad get depleted, the citric acid cycle will slow down and eventually stop. So again, our answer here is that our statement is false. The citric acid cycle cannot proceed if N A DH and FA DH two do not undergo re oxidation because the oxidized forms are needed for the reactions of the citric acid cycle that need those forms to take place. See you in the next video.

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21. The Generation of Biochemical Energy

The Citric Acid Cycle

GOB Chemistry

21. The Generation of Biochemical Energy

The Citric Acid Cycle

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2:07 minutes

Problem 68

Textbook Question

What would happen to the citric acid cycle if NADH and FADH₂ were not reoxidized?

Verified step by step guidance

Understand the role of NADH and FADH₂ in the citric acid cycle: These molecules are electron carriers that are reduced during the cycle. They transport electrons to the electron transport chain (ETC) where they are reoxidized to NAD⁺ and FAD, allowing the cycle to continue.

Recognize the importance of reoxidation: The reoxidation of NADH to NAD⁺ and FADH₂ to FAD is essential because the citric acid cycle requires NAD⁺ and FAD as reactants for key steps, such as the oxidation of isocitrate and succinate.

Consider the consequences of no reoxidation: If NADH and FADH₂ are not reoxidized, the levels of NAD⁺ and FAD would decrease, eventually halting the citric acid cycle because these cofactors would no longer be available to accept electrons during the cycle's reactions.

Understand the broader impact: Without the citric acid cycle functioning, the cell would be unable to produce sufficient ATP through oxidative phosphorylation, leading to a significant energy deficit.

Conclude the chain reaction: The lack of ATP production would impair cellular processes, potentially leading to cell death if alternative pathways (e.g., fermentation) cannot compensate for the energy shortfall.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Citric Acid Cycle

The citric acid cycle, also known as the Krebs cycle, is a series of enzymatic reactions that occur in the mitochondria, where acetyl-CoA is oxidized to produce energy. This cycle generates high-energy electron carriers, NADH and FADH₂, which are crucial for the subsequent production of ATP through oxidative phosphorylation.

NADH and FADH₂

NADH and FADH₂ are electron carriers produced during the citric acid cycle and other metabolic pathways. They play a vital role in cellular respiration by donating electrons to the electron transport chain, which ultimately leads to the synthesis of ATP. Their reoxidation is essential for maintaining the flow of the cycle and energy production.

Reoxidation Process

Reoxidation refers to the process by which NADH and FADH₂ are converted back to their oxidized forms, NAD⁺ and FAD, respectively. This process is critical for the continuation of the citric acid cycle and is primarily achieved through the electron transport chain. If reoxidation does not occur, the cycle would halt, leading to a depletion of NAD⁺ and FAD, ultimately disrupting ATP production.

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