A mutation to metabolize this compound has been the most surprising adaptation in 35 years (20[1])of the long-term E. coli evolution experiment. (20[1])Salts of this chelating (20[1])(“KEY-lating”) acid (20[1])are administered to neutralize stomach acid (20[1])before a C-section and to alkalinize (“ALK-uh-lin-ize”) urine to prevent kidney stones. The only iron-sulfur protein in central metabolism isomerizes this compound through aconitate. Glycolysis is feedback-inhibited (20[1])by (0[1])this (20[1])six-carbon (*) tri·carboxylic acid, (10[1]0[4])which is formed when (10[1])oxalo·acetate (10[1]0[1])condenses (10[1])with (10[1])acetyl-CoA. (0[2])Aerobic (10[1])oxidation of this compound (10[1]0[1])provides (10[1])high-energy electrons to (10[1])N·A·D (0[1])and F·A·D in a pathway (10[1])that occurs inside the mitochondrial matrix after glycolysis. (0[1])For 10 points, (0[1])the Krebs cycle is named for what (0[1])acid (10[1])found (0[1])in oranges (10[3])and lemons? (10[7])■END■ (10[7])