Summary
A cyclic pathway that oxidises acetyl-CoA to carbon dioxide, producing NADH, FADH2 and a little ATP.
In depth
Acetyl-CoA joins oxaloacetate to form citrate; the cycle regenerates oxaloacetate. Per turn: 3 NADH, 1 FADH2, 1 GTP/ATP and 2 CO2. Two turns per glucose. Intermediates feed biosynthesis (amino acids, haem). Hans Krebs described it in 1937.
The cycle runs twice per glucose. Its intermediates are also precursors for amino acids and haem. It is regulated by NADH, ATP and calcium.
Key idea: the cycle's main product is reduced coenzymes, not ATP.
Frequently asked questions
What is Krebs Cycle?
A cyclic pathway that oxidises acetyl-CoA to carbon dioxide, producing NADH, FADH2 and a little ATP.
Which area of biology covers Krebs Cycle, and how advanced is it?
Krebs Cycle is one of the 53 topics in Metabolism & Bioenergetics. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Link Reaction, Beta-Oxidation, Anabolism and Catabolism.
Can you give an example of Krebs Cycle?
Citrate is exported to make fatty acids.
What should I learn before Krebs Cycle?
Work through the Beginner topics in Metabolism & Bioenergetics first, such as Metabolism, Anabolism and Catabolism, ATP, then return to Krebs Cycle. Intermediate topics assume the Beginner vocabulary.
What topics are related to Krebs Cycle?
The closest topics to Krebs Cycle are Link Reaction, Beta-Oxidation, Anabolism and Catabolism, Glycolysis. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Krebs Cycle?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Krebs Cycle. To practise the whole of Metabolism & Bioenergetics, use the Metabolism & Bioenergetics quiz.
How is Krebs Cycle different from Link Reaction?
Krebs Cycle: A cyclic pathway that oxidises acetyl-CoA to carbon dioxide, producing NADH, FADH2 and a little ATP. Link Reaction: Pyruvate is oxidised to acetyl-CoA in the mitochondrial matrix, releasing carbon dioxide and forming NADH. Read both side by side and note what each one explains.
How should I study Krebs Cycle step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Link Reaction and explain the difference aloud. Finally, take the Metabolism & Bioenergetics quiz and come back to this page for any question you miss.