Exam 26: Amino Acid Metabolism

Coconut protein is biologically inferior because it is lacking many essential amino acids.In your efforts to make transgenic coconuts with protein of high biological value, you should definitely ensure that your coconut protein has an adequate amount of:

A newborn with acute encephalopathy is found to have hypoglycemia and ketonuria.Plasma leucine, isoleucine, and valine levels are markedly elevated, but the plasma ammonia level is normal.This is most likely a case of:

A negative nitrogen balance is most likely to be present in:

High homocysteine levels are associated with an increased risk of atherosclerosis.A deficiency of which of the following enzymes would result in high blood levels of homocysteine (and also methionine)?

A nurse notices that the urine produced by a newborn infant has the odor of maple syrup.Which of the following pathways is most likely defective?

A 2-week-old infant presents with vomiting, lethargy, and convulsions without evidence of an infectious process.Laboratory examination reveals hyperammonemia with alkalosis.Glutamine, citrulline, and arginine levels are found elevated in the blood.The enzyme that is most likely deficient in this patient is:

A 1-year-old child with mental retardation has a deficiency of dihydrobiopterin reductase.This enzyme deficiency leads to an increased blood level of:

A 2-week-old infant presents with vomiting, lethargy, and convulsions without evidence of an infectious process.Laboratory examination reveals hyperammonemia without acidosis.The diagnosis is a hereditary deficiency of N-acetylglutamate synthetase.N-acetylglutamate is an allosteric activator of:

The nitrogen balance is likely to be positive:

Quantitatively, the major metabolic fate of glycine in the body is: