Transport of Ammonia - Lecture Review

These flashcards cover key concepts related to the transport of ammonia, urea synthesis, and associated metabolic processes.

What is the primary site of ureogenesis in the human body?

The liver is the main site of ureogenesis.

What compounds are the end products of the urea cycle?

Urea and ornithine are produced as end products of the urea cycle.

Why is ammonia toxic to mammalian cells?

Accumulated ammonia depletes α-ketoglutarate, leading to reduced ATP synthesis and impaired active transport.

What role does glutamine play in the transport of ammonia?

Glutamine transports ammonia in the blood to the liver where it is converted to glutamate.

How does the alanine-glucose cycle contribute to ammonia transport?

Ammonia is transported as alanine to the liver, where it is converted to pyruvate and glutamate.

What is an allosteric activator required for carbamoyl phosphate synthetase I?

N-acetyl glutamate (NAG) is the allosteric activator required for this enzyme.

What happens to aspartate in the urea cycle?

Aspartate condenses with citrulline to form argininosuccinate in the cytosol.

List one symptom of hyperammonaemia due to inherited urea cycle defects.

Symptoms include lethargy, stupor, and CNS impairment.

What occurs in the mitochondria after fumarate is produced in the urea cycle?

Fumarate is converted into malate and then into oxaloacetate.

What dietary adjustments are made for patients with urea cycle defects?

They are provided with diets containing α-keto analogues of essential amino acids.