A 45-year-old man is brought to the emergency department by ambulance after vomiting blood. The patient reports that he only ate a small snack the morning before and had not eaten anything for over 24 hours. At the hospital, the patient is stabilized. He is admitted to a surgical floor and placed on NPO with a nasogastric tube set to intermittent suction. He has been previously diagnosed with liver cirrhosis. An esophagogastroduodenoscopy (EGD) has been planned for the next afternoon. At the time of endoscopy, some pathways were generating glucose to maintain serum glucose levels. Which of the following enzymes catalyzes the irreversible biochemical reaction of this process?
AGlucose-6-phosphate dehydrogenase
BGlycogen phosphorylase
CEnolase
DGlyceraldehyde-3-phosphate dehydrogenase
EFructose-1,6-bisphosphatase
To prepare for an endoscopy, a 27-year-old male was asked by the gastroenterologist to fast overnight for his 12 p.m. appointment the next day. Therefore, his last meal was dinner at 5 p.m. the day before the appointment. By 12 p.m. the day of the appointment, his primary source of glucose was being generated from gluconeogenesis, which occurs via the reversal of glycolysis with extra enzymes to bypass the irreversible steps in glycolysis. Which of the following irreversible steps of gluconeogenesis occurs in the mitochondria?
AGlucose-6-phosphate to glucose
BPyruvate to oxaloacetate
CPhosphoenolypyruvate to pyruvate
DGlucose-6-phosphate to 6-phosphogluconolactone
EFructose-1,6-bisphosphate to fructose-6-phosphate
A 26-year-old African American man comes to the physician because of a 3-day history of fatigue, back pain, and dark urine. One week ago, he developed a headache and was treated with aspirin. He does not smoke or use illicit drugs. Physical examination shows conjunctival pallor. A peripheral blood smear shows erythrocytes with inclusions of denatured hemoglobin. Which of the following enzymes is involved in providing precursors for nucleotide synthesis in this patient?
AGlucose-6-phosphatase
BCarbamoyl phosphate synthetase I
CPyruvate carboxylase
DTransaldolase
EEnolase
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