Final answer:
It is true that unconjugated bilirubin travels in the blood bound to albumin, as it is not water-soluble and requires the binding to transport to the liver for conjugation.
Step-by-step explanation:
The question revolves around whether unconjugated bilirubin is bound to albumin when it travels in the blood. The statement is true. Unconjugated bilirubin, which is a breakdown product of heme from red blood cells, is not water-soluble. Due to its hydrophobic nature, it cannot circulate freely in the blood. To assist in its transport to the liver for further processing, it binds to albumin, the major circulating protein in the bloodstream. Albumin has the capacity to bind various biological molecules due to its structure which contains hydrophobic pockets, making it ideal for transporting substances like bilirubin. In cases like unconjugated hyperbilirubinemia, the level of bilirubin in the blood can exceed the binding capacity of albumin, leading to complications such as kernicterus in infants.