H1-antihistamines work by binding to histamine H1 receptors in mast cells, smooth muscle, and endothelium in the body as well as in the tuberomammillary nucleus in the brain; H2-antihistamines bind to histamine H2 receptors in the upper gastrointestinal tract, primarily in the stomach.
3 NADH molecules and 1 FADH molecule is produced for every turn of the Krebs cycle. One molecule of glucose will result in two turns of the Krebs cycle because two pyruvate molecules are the result of one glucose molecule (pyruvate if fed into the Krebs cycle after it is converted into acetyl-CoA).
Krebs cycle: pyruvic acid is used to form NADH and FADH2 + 2 ATP. ETC: NADH and FADH2 and oxygen are used to form 32 ATP. The Fourth and Fifth Stages of Cellular Respiration (without oxygen present) Lactic Acid Fermentation: pyruvic acid + NADH ---> lactic acid + NAD positive and allows glycolysis to continue. Makes muscles sore and fatigued.