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).
The acetyl CoA units are oxidized up to CO2 and H2O in the Krebs Cycle. In terms of ATP, the yielding depends on the kind of yielding that is used for reduced cofactors: a) If during your course it is considered that each NADH.H+ yields 2.5 ATP and each FADH2 yields 1.5 ATP, then.