Urine is made of water and wastes..96% water and 4% wastes products of metabolism. Bile is produced by the liver to help in digestion and gives urine the yellow color. Urea is the major nitrogenous end product of protein metabolism and is the chief nitrogenous component of the urine. Liver converts ammonia to urea, which is then eliminated in urine. Uric Acid is a nitrogenous end product of protein and purine metabolism in the body. Creatinine is formed by the metabolism of creatine (which helps supply energy to muscles), which is found in muscle tissue and blood and normally excreted in the urine as a metabolic waste. Salts and organic compounds include sodium, chloride, calcium, potassium, phosphates, and sulfates.