A 20-year-old male with no significant medical history comes to you with a urine positive for fructose. He does not have diabetes mellitus. Which enzyme is most likely to be deficient in this patient?
APyruvate kinase
BLactase
CFructokinase
DAldolase B
A 2-day-old boy is examined on day of discharge from the newborn nursery. He was born at 39 weeks by vaginal delivery to a primigravid mother. The pregnancy and delivery were uncomplicated, and the baby has been stooling, urinating, and feeding normally. Both the patient’s mother and father have no known past medical history and are found to have normal hemoglobin electrophoresis results. Compared to adult hemoglobin, the infant’s predominant hemoglobin is most likely to exhibit which of the following properties?
ADecreased affinity for 2,3-bisphosphoglycerate
BMore likely to form hexagonal crystals
CMore likely to cause red blood cell sickling
DLower affinity for binding oxygen
EIncreased affinity for 2,3-bisphosphoglycerate
A 6-month-old boy is brought to the emergency department by his mother because of recurrent vomiting and yellowing of his eyes. The mother says that he has been eating poorly since she started weaning him off of breast milk 5 days ago. At this time, mashed vegetables and fruits were added to his diet. Examination shows scleral jaundice and dry mucous membranes. The tip of the liver is palpable 4 cm below the right costal margin. His serum glucose concentration is 47 mg/dL, serum alanine aminotransferase is 55 U/L, and serum aspartate aminotransferase is 66 U/L. Which of the following enzymes is most likely deficient?
AFructokinase
BGlucose-6-phosphatase
CGalactokinase
DGalactose-1 phosphate uridyltransferase
EAldolase B
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