Carbohydrate Metabolism · NEET PG Preparation Biochemistry
An adult male presents with chronic fatigue and dark pigmentation of the sclera (ochronosis). He also reports that his urine turns dark upon standing…
Practice question from Carbohydrate Metabolism (NEET PG Preparation Biochemistry), with the correct answer and a step-by-step solution.
medium · MCQ · Q-F84BB6
An adult male presents with chronic fatigue and dark pigmentation of the sclera (ochronosis). He also reports that his urine turns dark upon standing and exposure to air. This condition is caused by a metabolic defect in the degradation of which of the following amino acids, which is closely linked to carbohydrate-derived energy pathways?
- A.Phenylalanine and TyrosineCorrect answer
- B.Valine and Isoleucine
- C.Tryptophan
- D.Methionine
Solution
Alkaptonuria is caused by a deficiency of homogentisate 1,2-dioxygenase in the catabolic pathway of phenylalanine and tyrosine, leading to accumulation of homogentisic acid which darkens on oxidation.
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