Krebs Cycle (Citric Acid Cycle) Overview

Overview

• Also known as the citric acid cycle or tricarboxylic acid (TCA) cycle
• A series of chemical reactions that occur within the mitochondria
• Key process by which cells generate energy from the food they consume

Steps of the Krebs Cycle

1. Acetyl-CoA is converted into Citrate by the enzyme citrate synthase
2. Citrate is converted into Isocitrate by the enzyme aconitase
3. Isocitrate is converted into α-Ketoglutarate by the enzyme isocitrate dehydrogenase
4. α-Ketoglutarate is converted into NADH and CO2 by the enzyme α-ketoglutarate dehydrogenase
5. α-Ketoglutarate is converted into NADH and CO2 by the enzyme α-ketoglutarate dehydrogenase
6. α-Ketoglutarate is converted into Succinyl-CoA by the enzyme α-ketoglutarate dehydrogenase
7. Succinyl-CoA is converted into Succinate by the enzyme succinyl-CoA synthetase
8. Succinate is converted into Fumarate by the enzyme succinate dehydrogenase
9. Fumarate is converted into Malate by the enzyme fumarase
10. Malate is converted into Oxaloacetate by the enzyme malate dehydrogenase

Outputs of the Krebs Cycle

• ATP: 2 molecules produced per cycle
• NADH: 6 molecules produced per cycle
• FADH2: 2 molecules produced per cycle
• CO2: 2 molecules produced per cycle

Importance of the Krebs Cycle

• Generates energy for the cell through the production of ATP, NADH, and FADH2
• Plays a key role in the breakdown of carbohydrates, fats, and proteins
• Essential for the proper functioning of cells and the maintenance of life