BI110 Chapter 26: Module 26
Document Summary
Pyruvate is decarboxylated, its carboxyl group is removed as a one-carbon molecule of. Co2, which diffuses out of he mitochondria and out of the cell. The remaining two- carbon acetyl group is transferred to coenzyme a to form acetyl coa. The conversion of pyruvate to acetyl-coa is exergonic. Some of the released energy is captured by the reduction of nad+ to nadh, which carries hydrogen ions and electrons to the later stages of cellular respiration. Occurs in the mitochondrial matrix, acetyl-coa oxidized through a series of eight enzyme-catalyzed reactions. For each acetyl-coa molecule, the citric acid cycle releases two molecules of co2, three nadh, one fadh2, and one gtp or atp. Step 1 enzyme citrate synthase catalyzes transfer of 2-carbon acetyl group from coenzyme a to the 4-carbon molecule oxaloacetate to form 6-carbon citrate. A released and reused during pyruvate decarboxylation and citric acid cycle. Step 2 citrate isomerized into isocitrate (6-carbon) by enzyme aconitase.
