Question

Ornithine an amino acid is found
A. As an intermediate of urea synthesis
B. As an intermediate of methionine metabolism
C. As a major fraction of the connective tissue
D. In bile salts

Answer 1

Hint: Amino acids are the building components of the proteins. They have an alpha carbon to which an acidic and a basic group both are found. Depending upon the variable alkyl groups, various different types of amino acids are formed.

Complete answer: The proteins are digested to form the amino acids. The glutamic amino acid is formed. The deamination and the transamination of the glutamic acid result in the formation of the carbamoyl phosphate. This deamination process occurs with the help of the carbamoyl phosphate enzyme. The carbamoyl phosphate combines with the ornithine in the presence of the alpha ornithine synthetase enzyme to form citrulline. This citrulline then combines with the aspartic acid in the presence of the kinase enzyme to form the argininosuccinic acid. The argininosuccinic acid is converted to fumaric acid and arginine in the presence of the argininosuccinate enzyme. Finally, the arginine combines with water in the presence of the arginase enzyme to form ornithine and urea. All these above-stated processes occur in the liver and the liver cell matrix. Thus, we can conclude that ornithine, an amino acid, is formed as an intermediate of urea synthesis.
Hence, the correct answer is option (A).

Note: Ornithine is an important part of the Urea formation. The process of the formation of the urea occurs in the liver. The process of urea formation is also known as the ornithine cycle. It is also known as the Kreb cycle. It is also known as the arginine cycle.