Biochemistry - MCQ Practice Questions

A patient with galactosemia has a deficiency in which enzyme?

Pasteur effect refers to the inhibition of glycolysis by oxidative phosphorylation. In terms of ATP and citrate, which statement is correct?

In glycolysis, which step is irreversible under physiological conditions and requires a different enzyme during gluconeogenesis?

The Warburg effect describes increased glycolysis in cancer cells even in the presence of oxygen. Which enzyme is typically upregulated in cancer cells to support this?

A 6-month-old infant develops hypoglycemia, hepatomegaly, and lactic acidosis after feeding. Genetic testing reveals glucose-6-phosphatase deficiency (Type I Glycogen Storage Disease). Why does this cause lactic acidosis?

A competitive athlete is found to have a deficiency in muscle phosphorylase (McArdle disease). During intense exercise, which metabolic consequence is PRIMARY?

A patient with hemoglobin C disease (defect in β-globin) shows increased levels of fetal hemoglobin (HbF). Why might elevated HbF reduce hemolysis compared to HbS?

A 3-year-old child presents with hepatomegaly, growth retardation, and elevated liver transaminases. Enzyme assay shows deficiency of lysosomal acid glucosidase (Pompe disease/GSD Type II). Which carbohydrate accumulates PRIMARILY in lysosomes?

Which of the following correctly pairs a glycogen storage disease with its enzyme defect and primary organ affected?

Which monosaccharide cannot be directly metabolized by red blood cells due to lack of specific enzymes?

In the Pasteur effect, the inhibition of glycolysis by oxidative phosphorylation is primarily mediated by which molecule(s)?

A newborn presents with jaundice, hepatomegaly, and infantile cataracts. Laboratory findings show elevated galactose in blood and urine. Which enzyme deficiency is most likely?

A 45-year-old male presents with chronic hyperuricemia and gout. Testing reveals elevated lactic acid and hepatomegaly. Which GSD is most likely?

In the Cori cycle, lactate produced in muscle is converted to glucose in the liver. Which enzyme is crucial for the final step in hepatic gluconeogenesis?

Which adaptation occurs in skeletal muscle during prolonged fasting (>48 hours)?

A patient with G6PD deficiency may develop hemolytic anemia upon exposure to oxidative stress. This occurs because:

Which of the following correctly describes the allosteric regulation of glycogen phosphorylase in muscle?

In maple syrup urine disease (MSUD), accumulation of branched-chain amino acids affects carbohydrate metabolism by:

Which statement accurately describes the relationship between blood glucose regulation and the Warburg effect in cancer cells?

Which statement best explains the structural basis for the higher energy content of glucose compared to other hexoses?