Which of the following is a function of the liver?

• A. Ammonia conversion
• B. Zinc storage
• C. Oxygen transport in blood
• D. Hormone production in pancreas

Answer: (A)

The main concept is nitrogen metabolism and detoxification by the liver. Ammonia is a toxic byproduct of protein breakdown. The liver converts this ammonia into urea through the urea cycle so it can be safely eliminated by the kidneys. This detoxification of ammonia is a central hepatic function and protects the brain from ammonia toxicity (hepatic encephalopathy) when liver function is impaired.

The other options point to functions not primarily performed by the liver: oxygen transport in the blood is carried by hemoglobin in red blood cells; hormone production in the pancreas is a pancreatic endocrine function; zinc storage occurs in multiple tissues and while the liver may store trace minerals, its main role is not zinc storage.