For 10 points, name this three-atom molecule essential to life, with chemical formula H2O.
This substance is regulated by proteins that have an aromatic/arginine selectivity filter; those proteins, which are made from six alpha helices, also contain the highly conserved NPA motif. Those proteins have an "hourglass" structure that aids the passage of this substance into the cell. The discovery of those proteins won Peter Agre the (*) 2003 Nobel Prize in Chemistry. Principal cells have V2 receptors for a hormone similar to oxytocin that responds to increased plasma osmolality by increasing the reabsorption of this substance through the creation of channels. Vasopressin or ADH is secreted from the pituitary and causes the collecting ducts in the nephron to reabsorb more of this substance by inserting aquaporin-2. For 10 points, name this three-atom molecule essential to life, with chemical formula H2O.
This substance is regulated by proteins that have an aromatic/arginine selectivity filter; those proteins, which are made from six alpha helices, also contain the highly conserved NPA motif.
water [accept H2O; accept dihydrogen monoxide]