urea

Which of the following is an allosteric activator of mammalian carbamoyl-phosphate synthetase?

• A) α-ketoglutarate

• B) N-acetylaspartate

• C) N-acetylglutamate

• D) Glutamine

• E) None of the above

In the urea cycle, the second nitrogen of urea enters the cycle in the form of which of the following metabolites?

• A) Alanine

• B) Glutamine

• C) Ornithine

• D) Aspartate

• E) Arginine

In the urea cycle, free NH3 is coupled with carboxyphosphate to form

• A) ureatic phosphate.

• B) pyruvate

• C) carbamic acid.

• D) All of the above.

• E) None of the above.

Which amino acid(s) are metabolites in the urea cycle, but are not used as building blocks of proteins?

• A) Ornithine

• B) Citrilline

• C) Glutamate

• D) A and B

• E) A, B, and C

In the urea cycle, the carbon skeleton of aspartate is preserved as

• A) succinate.

• B) fumarate.

• C) urea.

• D) All of the above.

• E) None of the above.