Preclinical Quiz

Which enzyme links glycolysis with the TCA cycle?

Which lipoprotein carries cholesterol from tissues to the liver?

Which vitamin acts as a coenzyme in transamination?

Name the major antioxidant present in RBCs.

Which bond is responsible for the secondary structure of proteins?

The committed step in cholesterol biosynthesis is catalyzed by:

• HMG-CoA lyase

• HMG-CoA reductase

• Squalene synthase

• Mevalonate kinase

In the urea cycle, which amino acid serves as both a substrate and a product?

• Ornithine

• Citrulline

• Aspartate

• Argininosuccinate

Which enzyme deficiency causes maple syrup urine disease?

• Branched-chain α-ketoacid dehydrogenase complex

• Pyruvate dehydrogenase complex

• Isocitrate dehydrogenase

• α-Ketoglutarate dehydrogenase

All are true about oxidative phosphorylation EXCEPT:

• Oligomycin inhibits ATP synthase

• Uncouplers increase oxygen consumption

• Cyanide inhibits cytochrome oxidase (Complex IV)

• Rotenone inhibits ATP synthase

Which enzyme deficiency is classically associated with hemolytic anemia due to impaired defense against oxidative stress?

• Glucose-6-phosphatase

• Glucose-6-phosphate dehydrogenase

• Pyruvate kinase

• Hexokinase