RNA is a very similar molecule to DNA, and only has two chemical differences. The overall structure of RNA and DNA are immensely similarâone strand of DNA and one of RNA can bind to form a double helical structure.NA also uses a different set of bases than DNAâ adenine, guanine, cytosine and uracil, instead of adenine, guanine, cytosine and thymine. Chemically, uracil is similar to thymine, differing only by a methyl group, and its production requires less energy.
Symptoms of a blocked bile duct include: 1  Yellowing of the skin (jaundice) or eyes (icterus), from the buildup of a waste product called bilirubin. 2  Itching (not limited to one area; may be worse at night or in warm weather) 3  Light brown urine. 4  Fatigue. Weight loss.  Fever or night sweats.
When one or more bile ducts narrows or has a blockage, bile may back up and cause problems such as jaundice, a yellowing of the skin. Or, a leak in a bile duct may allow bile to flow into the abdominal cavity. PTC allows your doctor to see on the x-rays if the ducts are partially or completely blocked.