Diagnostic markers of urea cycle function — Flashcards

Flashcard 1: Hyperammonemia results in excess NH3, which depletes _____, leading to inhibition of the TCA cycle

Answer: α-ketoglutarate

Flashcard 2: Does carbamoyl phosphate synthetase I deficiency present with orotic aciduria? _____

Answer: No

Flashcard 3: Ornithine transcarbamylase (OTC) deficiency presents with _____ BUN

Answer: decreased

Flashcard 4: Most disorders of the urea cycle require _____ as an essential amino acid, particularly during episodes of hyperammonemia

Answer: arginine

Flashcard 5: Does orotic aciduria present with hyperammonemia?_____

Answer: No

Flashcard 6: What is the most common urea cycle disorder? _____

Answer: Ornithine transcarbamylase (OTC) deficiency

Flashcard 7: Disorders of the urea cycle interfere with the body's ability to eliminate _____

Answer: ammonia (NH3)

Flashcard 8: Where does the urea cycle occur?

Answer: steps in both the cytoplasm and mitochondria

Flashcard 9: What is the rate-limiting enzyme of the Urea Cycle?

Answer: Carbamoyl phosphate synthetase I (CPS I)

Extra: CPS I is the rate-limiting enzyme of the urea cycle and is activated by N-acetylglutamate (NAG). It is located in the mitochondria.

Flashcard 10: What is the overall purpose of the urea cycle?

Answer: to get NH4+ from amino acid catabolism into an excretable form