Final answer:
New bicarbonate ions generated via glutamine metabolism in the kidney contribute primarily to maintaining acid-base balance by ensuring that for every ammonium ion excreted in the urine, a bicarbonate ion is retained in the blood.
Step-by-step explanation:
The role of new bicarbonate ions generated via glutamine metabolism in the kidney is primarily to help in maintaining acid-base balance in the body. This process occurs in the cells of the Proximal Convoluted Tubule (PCT), where the amino acid glutamine is deaminated. As a result, ammonia is pumped into the lumen, and for each ammonium ion excreted, a bicarbonate ion is gained in the blood, thus contributing to the acid-base balance. The kidneys play a crucial role in regulating acid-base homeostasis, reabsorbing or secreting hydrogen ions and bicarbonate as needed to maintain the pH within the proper range.
While the presence of aquaporin channels allows water to be reabsorbed through osmosis, this does not directly relate to bicarbonate ions and their role in acid-base balance. In addition, the generated bicarbonate ions do not play a role in the synthesis of urea. Urea formation involves the liver and is a separate process from the renal handling of bicarbonate ions.