The Krebs Cycle

The Krebs Cycle

• Also known as the citric acid cycle.

  • The Krebs cycle begins with each molecule of acetyl-CoA produced from the second stage of Aerobic Respiration combining with oxaloacetate, a four-carbon molecule, to form a six-carbon molecule, citric acid or citrate.

  • In the mitochondria, pyruvate is turned into acetyl- CoA and 1 NADH is made; double this if you are counting per Glucose.

  • The Krebs cycle occurs in the mitochondrial matrix.

  • It begins with acetyl-CoA joining with oxaloacetate to make citric acid and ends with oxaloacetate, 1 ATP, 3 NADH, and 1 FADH2; double this if you are counting per Glucose.

  • Citrate gets turned into several other things, and because the cycle begins with a four-carbon molecule, oxaloacetate, it eventually gets turned back into oxaloacetate to maintain the cycle by joining with the next acetyl-CoA coming down the pipeline.

• With each turn of the cycle, three types of energy are produced:

  • 1 ATP

  • 3 NADH

  • 1 FADH2

• To figure out the total number of products per molecule of Glucose, we simply double the number of products.