Question 1

Which cofactor is required for all amino acid degradation pathways in the first transamination reaction?

Accepted Answer

Pyridoxine (Vitamin B6)

Question 2

In the liver mitochondria, glutamate is converted to α-ketoglutarate by a process that can be described as:

Accepted Answer

Oxidative deamination

Question 3

The amino acids serine, cysteine, and alanine are catabolized to yield which intermediate of the citric acid cycle?

Accepted Answer

Pyruvate

Question 4

Phenylketonuria (PKU) results from which of the following?

Accepted Answer

Inability to convert phenylalanine to tyrosine

Question 5

Which amino acid is directly involved with complex II of the electron transport chain?

Accepted Answer

Succinate

Question 6

Which of the following best describes the role of transamination in amino acid metabolism?

Accepted Answer

Transfer of the amino group to α-ketoglutarate

Question 7

A patient with a deficiency in pyridoxal phosphate would most likely have difficulty with which metabolic process?

Accepted Answer

Transamination reactions

Question 8

Which of the following is a direct product of the oxidative deamination of glutamate?

Accepted Answer

Ammonia ($$NH_3)$$

Question 9

Which enzyme catalyzes the conversion of phenylalanine to tyrosine?

Accepted Answer

Phenylalanine hydroxylase

Question 10

A defect in which enzyme would most likely result in the accumulation of phenylalanine and the clinical symptoms of PKU?

Accepted Answer

Phenylalanine hydroxylase

Question 11

Which of the following reactions is catalyzed by aminotransferases?

Accepted Answer

$$\alpha-$$amino acid + \alpha$$-ketoglutarate \rightarrow \alpha-$$keto acid + glutamate$

Question 12

Which vitamin deficiency would most likely impair the function of aminotransferases?

Accepted Answer

Vitamin B6 (pyridoxine)

Question 13

Which of the following best explains why PKU patients must avoid aspartame?

Accepted Answer

Aspartame contains phenylalanine

Question 14

Which of the following is a common fate of the carbon skeletons of amino acids after deamination?

Accepted Answer

Conversion to glucose via gluconeogenesis

Question 15

Which of the following best describes the fate of the amino group removed during amino acid catabolism?

Accepted Answer

It is converted to urea in the liver

Amino Acid Oxidation and Metabolism: Practice Questions and Key Concepts

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