BCHEM Test 4: Amino Acid Degradation

Name three tissues/organs that are particularly important for amino acid metabolism.

Liver, skeletal muscle and kidneys are very important for amino acid metabolism. Intestines are critical for amino acid uptake.

The degradation of an amino acid generates only oxaloacetate. This amino acid is a ____. A) Glucogenic amino acid. B) Ketogenic amino acid. C) Both glucogenic and ketogenic amino acid. D) Cannot be determined based on the above information.

A

Which of the following statement is true about the deamination of glutamate by glutamate dehydrogenase? (Select ALL that apply) A) This reaction removes the α-amino group from glutamate. B) This reaction generates ammonia. C) This reaction generates ATP. D) This reaction generates a high-energy molecule that can be used for ATP generation in mitochondria. E) This reaction is exergonic and irreversible.

A, B, D

Which of the following statements correctly indicates the subcellular localizations of metabolic pathways? (Select ALL that apply) A) Gluconeogenesis takes place in mitochondria, cytosol and ER. B) Transamination reactions occur in cytoplasm and mitochondria. C) The reaction catalyzed by glutamate dehydrogenase takes place in cytoplasm. D) Urea Cycle occurs in cytosol and mitochondria. E) Ketogenesis and ketone body degradation occur in mitochondria.

A, B, D, E

Which of the following metabolic pathways involve hydrolysis of ATP? (Select ALL that apply) A) Glycolysis. B) Citrate Acid Cycle. C) ETC/OxPhos. D) Fatty acid synthesis. E) Fatty acid degradation. F) Ketogenesis G) Gluconeogenesis. H) Deamination of glutamate I) Urea Cycle.

A, D, E, G, I

Which of the following statements correctly describes amino acid transport and metabolism during fasting/starvation state? (Select ALL that apply) A) Branch-chain amino acids are transported into liver. B) Alanine is transported from skeletal muscle to liver. C) Glutamine is transported from skeletal muscle to kidney. D) Glutamate is deaminated in liver and kidney cells. E) Urea is made by liver and kidney cells.

B, C, D

Which of the following molecules is an amino acid but is not used as a building block for protein synthesis? A) glutamate. B) citrulline. C) aspartate. D) ornithine. E) tryptophan.

B, D

Which of the following statements is true about Urea Cycle? (Select ALL that apply) A) Both of two nitrogen atoms in urea molecule are from ammonia. B) CPS-I catalyzes the generation of carbomoyl phosphate from bicarbonate, ammonia and ATP. C) All reactions in urea cycle take place in mitochondria. D) Amino acids aspartate, ornithine and citrulline take part in the Urea Cycle.

B, D

Surplus amino acids from food digestion are? A) stored in proteasome. B) stored in some forms of proteins C) degraded to support biosynthesis and provide energy D) All of the above. E) None of the above.

C

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.

C

Which of the following statements is true about transamination reactions? A) Transamination reactions transfer amino groups from α-amino acids to any carboxylic acids. B) Transamination reactions are exergonic and irreversible. C) Transamination reactions generate ammonia. D) Transamination reactions are involved in malate-aspartate shuttle and pyruvate-alanine cycle.

D