Unit 4 Exam UNE CHEM 1005
Questions and Answers 2025-2026
Edition.
A deficiency in vitamin B6 (pyridoxal phosphate) would negatively impact which of the following
pathways:
Metabolism of cysteine to homocysteine
Metabolism of phenylalanine to tyrosine
Conversion of methyl malonyl-Co A to succinyl-CoA
1 only
2 only
2 and 3
1 and 2 - Answer 1 only
In an individual with a deficiency in the branched-chain ketoacid dehydrogenase complex,
metabolism of which of the following amino acids would not likely be impaired?
Leucine
Tyrosine
Valine
Isoleucine - Answer Tyrosine
Which of the following best describes the process of transamination?
The transfer of a carboxyl group to a ketoacid
The transfer of an amino group from an amino acid to a ketoacid
The release of free ammonia from an amino acid
The transfer of an amino group to glucose - Answer The transfer of an amino group from an
amino acid to a ketoacid
A 52-year-old male sought medical attention due to the progressive appearance of
hyperchromic (hyperpigmented) papules on the edge of the second finger of both hands and
darkening of his urine. Tissue biopsy and urine sample tested positive for homogentisic acid.
Questions and Answers 2025-2026
Edition.
A deficiency in vitamin B6 (pyridoxal phosphate) would negatively impact which of the following
pathways:
Metabolism of cysteine to homocysteine
Metabolism of phenylalanine to tyrosine
Conversion of methyl malonyl-Co A to succinyl-CoA
1 only
2 only
2 and 3
1 and 2 - Answer 1 only
In an individual with a deficiency in the branched-chain ketoacid dehydrogenase complex,
metabolism of which of the following amino acids would not likely be impaired?
Leucine
Tyrosine
Valine
Isoleucine - Answer Tyrosine
Which of the following best describes the process of transamination?
The transfer of a carboxyl group to a ketoacid
The transfer of an amino group from an amino acid to a ketoacid
The release of free ammonia from an amino acid
The transfer of an amino group to glucose - Answer The transfer of an amino group from an
amino acid to a ketoacid
A 52-year-old male sought medical attention due to the progressive appearance of
hyperchromic (hyperpigmented) papules on the edge of the second finger of both hands and
darkening of his urine. Tissue biopsy and urine sample tested positive for homogentisic acid.
