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HomeHomework HelpbiologyKrebs Cycle

Krebs Cycle

The Krebs cycle, also known as the citric acid cycle, is a series of enzymatic reactions that occur in the mitochondria of cells, where acetyl-CoA is oxidized to produce carbon dioxide, ATP, and high-energy electron carriers (NADH and FADH2) as part of cellular respiration. This cycle plays a crucial role in energy metabolism by linking carbohydrate, fat, and protein catabolism.

intermediate
2 hours
Biology
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Overview

The Krebs cycle, also known as the citric acid cycle, is a vital metabolic pathway that plays a key role in cellular respiration. It takes place in the mitochondria and involves a series of chemical reactions that convert Acetyl-CoA into energy carriers like NADH and FADH2, while releasing carbon di...

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Key Terms

Acetyl-CoA
A molecule that enters the Krebs cycle, derived from carbohydrates, fats, and proteins.

Example: Acetyl-CoA is produced from pyruvate during glycolysis.

NADH
An energy carrier produced in the Krebs cycle that donates electrons to the electron transport chain.

Example: NADH is generated during the conversion of isocitrate to alpha-ketoglutarate.

FADH2
Another energy carrier produced in the Krebs cycle, similar to NADH but with a lower energy yield.

Example: FADH2 is produced during the conversion of succinate to fumarate.

ATP
A high-energy molecule that serves as the primary energy currency of the cell.

Example: ATP is generated during the substrate-level phosphorylation in the Krebs cycle.

Enzyme
A protein that accelerates chemical reactions in the body, including those in the Krebs cycle.

Example: Citrate synthase is an enzyme that catalyzes the first step of the Krebs cycle.

Citric Acid
The first product formed in the Krebs cycle, derived from Acetyl-CoA and oxaloacetate.

Example: Citric acid is also known as lemon acid, found in citrus fruits.

Related Topics

Glycolysis
The process of breaking down glucose to form pyruvate, which feeds into the Krebs cycle.
intermediate
Electron Transport Chain
The final stage of cellular respiration where ATP is produced using NADH and FADH2.
advanced
Photosynthesis
The process by which plants convert light energy into chemical energy, contrasting with cellular respiration.
intermediate

Key Concepts

Energy productionAcetyl-CoANADH and FADH2Carbon dioxide release