Amino Acid Oxidation and the Production of Urea

Under what metabolic circumstance do amino acids undergo oxidative degradation in animals?

What is the primary role of the hormone gastrin in the context of protein digestion?

What is the function of the coenzyme pyridoxal phosphate (PLP) in the first step of amino acid catabolism?

Which enzyme is unique in its ability to use either NAD+ or NADP+ as the acceptor of reducing equivalents during the oxidative deamination of glutamate in mammals?

What is the primary role of the glucose-alanine cycle?

What is the immediate fate of the first amino group that enters the urea cycle in liver mitochondria?

How many high-energy phosphate groups are consumed in the synthesis of one molecule of urea?

How is the energetic cost of urea synthesis partially ameliorated or reduced in the cell?

Which two amino acids are exclusively ketogenic, meaning they are degraded to acetyl-CoA or acetoacetyl-CoA but cannot be converted to glucose?

What is the role of tetrahydrofolate in amino acid catabolism?

What disease is caused by a genetic defect in the enzyme phenylalanine hydroxylase?

The degradation of which group of six amino acids leads to the production of pyruvate?

The catabolism of the branched-chain amino acids (leucine, isoleucine, and valine) is initiated in which primary tissues in mammals?

What is the consequence of a genetic defect in the branched-chain alpha-keto acid dehydrogenase complex?

How many of the 20 common amino acids can be degraded, in whole or in part, to yield succinyl-CoA?

What is the source of the two nitrogen atoms in the urea molecule produced by the urea cycle?

Which cofactor is required for the conversion of serine to glycine by serine hydroxymethyltransferase?

Which of the following is NOT a characteristic of the enzyme complex that degrades branched-chain alpha-keto acids?

What is the metabolic fate of the four-carbon fragment fumarate that is produced during the degradation of phenylalanine and tyrosine?

Which enzyme catalyzes the final step of the urea cycle, cleaving arginine to yield urea and ornithine?

A deficiency in which coenzyme is associated with the disease pernicious anemia?

What is the primary function of S-adenosylmethionine (adoMet) in amino acid catabolism?

The catabolism of five specific amino acids results in the formation of alpha-ketoglutarate. Which of the following amino acids is part of this group?

What is the common intermediate that links the urea cycle and the citric acid cycle in the 'Krebs bicycle'?

The degradation of tryptophan is the most complex of all amino acid catabolic pathways. Which important molecule is synthesized from intermediates in this pathway?

A patient with a genetic deficiency in carbamoyl phosphate synthetase I would likely be treated with a diet that is:

What is the function of the enzyme glutaminase in the liver and kidney?

How many of the 20 common amino acids are considered essential for humans, meaning they must be provided in the diet?

In the catabolism of serine, the enzyme serine dehydratase removes the alpha-amino and beta-hydroxyl groups, producing pyruvate. This reaction requires which coenzyme?

What is the primary product of the catabolism of asparagine and aspartate?

The glycine cleavage enzyme complex oxidizes glycine to CO2 and NH4+. What is the fate of the second carbon atom of glycine in this reaction?

In the degradation of threonine to propionyl-CoA, what is the initial step catalyzed by threonine dehydratase?

The catabolism of methionine yields propionyl-CoA. What is the role of S-adenosylmethionine (adoMet) in this process?

What is the common metabolic intermediate through which the carbon skeletons of isoleucine, methionine, threonine, and valine enter the citric acid cycle?

In individuals with alkaptonuria, the urine turns dark upon standing due to the accumulation and oxidation of which metabolic intermediate?

What is the primary purpose of the two-step glutaminase and glutamate dehydrogenase reactions in the liver?

The catabolism of histidine to alpha-ketoglutarate involves the transfer of a one-carbon group. Which coenzyme acts as the acceptor for this one-carbon group?

What is the function of the enzyme enteropeptidase in the digestive tract?

Which condition results from a genetic defect in homogentisate 1,2-dioxygenase?

The catabolism of which amino acid provides the sulfur atom for the synthesis of cysteine in mammals?

In the reaction catalyzed by glutamine synthetase, what is the high-energy intermediate formed from glutamate and ATP?

Which cofactor is required for the conversion of L-methylmalonyl-CoA to succinyl-CoA?

Which of the following amino acids is both glucogenic and ketogenic?

What is the function of the hormone cholecystokinin?

In the transdeamination pathway, what is the role of glutamate dehydrogenase?

What is the biochemical reason for ammonia toxicity in the brain?

How many of the seven amino acids that yield acetyl-CoA are also glucogenic?

What is the primary excretory form of nitrogen in most terrestrial vertebrates?

In the degradation of isoleucine, the carbon skeleton is ultimately cleaved into which two products?

What is the common intermediate formed from the catabolism of arginine, histidine, glutamine, and proline?