Proteins LM5: Amino Acid Catabolism

The adult liver generally prefers to: a. Metabolize branched chain amino acids b. Metabolize aromatic amino acids c. Catabolize urea d. Oxidize ketone bodies e. Produce "false" neurotransmitters

• Metabolize branched chain amino acids

• Metabolize aromatic amino acids

• Catabolize urea

• Oxidize ketone bodies

• Produce "false" neurotransmitters

Which one of the following amino acids is a favored substrate of the intestine? a. Phe b. Trp c. Ala d. Gln e. Val

• Phe

• Trp

• Ala

• Gln

• Val

Which one of the following amino acids, produced from pyruvate and ammonium ion, is released from skeletal muscle tissue at a high rate during starvation? a. Ala b. Gln c. Val d. Ser e. Tyr

• Ala

• Gln

• Val

• Ser

• Tyr

Which one of the following is the preferred amino acid substrate of brain tissue during starvation? a. Gln b. Glu c. Val d. Leu e. Ala

• Gln

• Glu

• Val

• Leu

• Ala

Which one of the following amino acids can be used to form ketone bodies in the liver, but not glucose? a. Leu b. Cys c. Met d. Glu e. Phe

• Leu

• Cys

• Met

• Glu

• Phe

Pregnancy is generally associated with: a. A significant decrease in the plasma BCAA:AAA ratio. b. A negative nitrogen balance. c. Decreased clearance of "false" neurotransmitters from the hepatic portal circulation. d. A positive nitrogen balance. e. Hepatoencephalopathy

• A significant decrease in the plasma BCAA:AAA ratio.

• A negative nitrogen balance.

• Decreased clearance of "false" neurotransmitters from the hepatic portal circulation.

• A positive nitrogen balance.

• Hepatoencephalopathy

All of the following are associated with a negative nitrogen balance, EXCEPT: a. Insulin excess b. Glucocorticoid excess c. An essential amino acid deficiency d. Traumatic injury e. Infection

• Insulin excess

• Glucocorticoid excess

• An essential amino acid deficiency

• Traumatic injury

• Infection

The cofactor reductant involved in the hepatic conversion of Phe to Tyr is: a. Tetrahydrofolate b. NADH c. Tetrahydrobiopterin d. Folate e. Biotin

• Tetrahydrofolate

• NADH

• Tetrahydrobiopterin

• Folate

• Biotin

Which one of the following amino acids is both glucogenic and ketogenic? a. Gly b. Lys c. Met d. Gln e. Phe

• Gly

• Lys

• Met

• Gln

• Phe

PKU is best associated with a deficiency in: a. Folic acid reductase. b. Phenylalanine hydroxylase. c. Dihydropteridine reductase. d. Folate. e. Phe.

• Folic acid reductase.

• Phenylalanine hydroxylase.

• Dihydropteridine reductase.

• Folate.

• Phe.