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Old 10-02-2011
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Biochemistry Glucose Galactose Question!

A newborn infant presents with poor feeding, vomiting, jaundice, and an enlarged liver. The urine tests positive for reducing substances, indicating the presence of sugars with aldehyde groups. Which of the following processes is most likely to be abnormal?
A. Conversion of glucose to galactose
B. Conversion of lactose to galactose
C. Conversion of activated galactose to activated glucose
D. Excretion of glucose by the kidney
E. Excretion of galactose by the kidney
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Old 10-02-2011
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A newborn infant presents with poor feeding, vomiting, jaundice, and an enlarged liver. The urine tests positive for reducing substances, indicating the presence of sugars with aldehyde groups. Which of the following processes is most likely to be abnormal?
A.Conversion of glucose to galactose
B.Conversion of lactose to galactose
C.Conversion of activated galactose to activated glucose
D.Excretion of glucose by the kidney
E.Excretion of galactose by the kidney
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Old 10-02-2011
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C is the answer
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Old 10-02-2011
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The answer is: C
This infant may have galactosemia , a deficiency of galactose-1 phosphate uridyl transferase (GALT). Galactose from lactose in breast milk or infant formula is phosphorylated by galactokinase, activated to uridine diphosphogalactose (UDP-galactose) by GALT, and converted to UDP-glucose by UDP-galactose epimerase. The elevation of galactose metabolites is thought to cause liver toxicity, and their urinary excretion produces reducing substances. Infants with the signs and symptoms listed are placed on lactose-free formulas until enzyme testing is complete. Deficiencies of epimerase or kinase can cause mild forms of galactosemia.
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Old 10-02-2011
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Where are these questions from?
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C. Conversion of activated galactose to activated glucose
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