How many NADH and how many FADH 2 molecules are formed in the citric acid cycle?

Hi, everyone. Let's look at the next question during the Krebs cycle. How many molecules of N A DH slash H plus? And fa DH two are produced for each molecule of pyruvate? Well, this is something we definitely should just know about the creb cycle. So when it comes to N A DH, the cycle yields for every molecule of Ayl Ka that enters the cycle. We have three molecules of N A DH and one molecule of fa DH two, our N A plus is getting reduced. So there's three oxidation steps in which this occurs. So our first one is the conversion of isocitrate to alpha ketoglutarate. And then the second oxidation reaction is the oxidation of alpha ketoglutarate to succinyl coa. And finally, that third molecule is going to come from the oxidation of malate to oxalacetate. As you can see three different oxidation reactions accounting for the three molecules of N A DH that are produced. And then our step that produces FA DH two is the oxidation of succinate to fumarate. So there we have it, we have our three oxidation steps that produce N A DH. And one oxidation step that produces fa DH two giving us a total of three molecules of N A DH and one molecule of FA DH two. See you in the next video.

Table of contents

Skip topic navigation

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

21. The Generation of Biochemical Energy

The Citric Acid Cycle

GOB Chemistry

21. The Generation of Biochemical Energy

The Citric Acid Cycle

Previous problemNext problem

1:56 minutes

Problem 56

Textbook Question

How many NADH and how many FADH₂ molecules are formed in the citric acid cycle?

Verified step by step guidance

Understand the citric acid cycle: The citric acid cycle (also known as the Krebs cycle or TCA cycle) is a series of chemical reactions used by aerobic organisms to generate energy through the oxidation of acetyl-CoA. It also produces electron carriers like NADH and FADH2, which are used in the electron transport chain to produce ATP.

Identify the key steps in the citric acid cycle where NADH is produced: NADH is formed during three specific reactions in the cycle. These occur during the oxidation of isocitrate to α-ketoglutarate, the oxidation of α-ketoglutarate to succinyl-CoA, and the oxidation of malate to oxaloacetate.

Identify the step in the citric acid cycle where FADH2 is produced: FADH2 is formed during the oxidation of succinate to fumarate, which is catalyzed by the enzyme succinate dehydrogenase.

Count the number of NADH molecules produced per turn of the cycle: Since there are three reactions that produce NADH, one turn of the citric acid cycle generates three NADH molecules.

Count the number of FADH2 molecules produced per turn of the cycle: Since there is one reaction that produces FADH2, one turn of the citric acid cycle generates one FADH2 molecule.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

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 chemical reactions used by all aerobic organisms to generate energy. It occurs in the mitochondria and is a key component of cellular respiration, where acetyl-CoA is oxidized to produce energy carriers, including NADH and FADH2.

NADH and FADH2

NADH and FADH2 are electron carriers produced during the citric acid cycle. NADH is generated from the reduction of NAD+ during specific reactions, while FADH2 is produced from the reduction of FAD. Both molecules play a crucial role in the electron transport chain, where they help generate ATP.

Energy Yield

The energy yield from the citric acid cycle is significant, as it produces three NADH and one FADH2 per turn of the cycle. Since each NADH can generate approximately 2.5 ATP and each FADH2 about 1.5 ATP during oxidative phosphorylation, understanding their production is essential for calculating the total energy output from glucose metabolism.

Watch next

Master Phase A - Citrate Formation Concept 1 with a bite sized video explanation from Jules

Start learning