5.5 The Krebs Cycle

5.5 The Krebs Cycle “GROOMING” Pyruvate from Glycolysis is transported into the mitochondria. A CO2 is removed, resulting in a 2-carbon molecule, acetate (or acetic acid). NAD+ is reduced to NADH, and Coenzyme A (CoA) bonds to acetate to form Acetyl CoA.

5.5 The Krebs Cycle “GROOMING” Happens in between Glycolysis & Kreb’s Cycle (mitochondria) Coenzyme A = a carrier molecule; brings acetate into cycle Produces 1 CO2 & 1 NADH

5.5 The Krebs Cycle 1. Acetyl CoA combines the with a 4-C acid (oxaloacetate) to form a 6-C citrate. CoA is released & recycled to carry more acetate.

5.5 The Krebs Cycle 2. A carbon atom from citrate is oxidized and released as CO2; NAD+ is reduced to NADH, & a 5-C sugar, ketoglutarate results.

5.5 The Krebs Cycle 3. A carbon atom from ketoglutarate is oxidized and released as CO2, another molecule of NAD+ is reduced to NADH, & 4-carbon sugar results.

5.5 The Krebs Cycle 4. The 4-C molecule is rearranged & oxidized, which reduces an NAD+ to NADH, an FAD to FADH2, and creates a molecule of ATP. This forms oxaloacetate (which starts the cycle).

Summary of Glycolysis & Krebs Cycle Products   Location Raw Materials ATP NADH FADH2 Other Glycolysis Cytoplasm Glucose 2 2 Pyruvates "Grooming" Mitochondria Pyruvate 2 Acetyl CoA 2 Carbon dioxide Krebs Cycle Mitochondrial Matrix Acetyl CoA (also will need oxygen) 6 4 Carbon Dioxide