Final answer:
1) Yes Conjugated bilirubin is water soluble due to its conjugation with glucuronic acid in the liver, making it excretable via the bile duct into the intestine.
Step-by-step explanation:
Yes, conjugated bilirubin is water soluble. The process of making bilirubin water soluble occurs in the liver, where bilirubin is conjugated with glucuronic acid through the enzyme UDP glucuronyl transferase, resulting in bilirubin monoglucuronide and bilirubin diglucuronide.
This conjugation makes bilirubin water soluble, allowing it to be easily excreted out of the body via the bile duct into the intestine. Unconjugated bilirubin is not water soluble and thus must undergo this conjugation process to be excreted.
The Van Den Bergh test demonstrates this solubility difference; direct bilirubin or conjugated bilirubin reacts with Diazo reagent, whereas unconjugated bilirubin does not without the presence of alcohol.