Enzyme Kinetics and Michaelis-Menten Equation Practice Questions

Question 1

Which of the following represents the most significant regulatory control point among these TCA cycle reactions?

Accepted Answer

Isocitrate to Alpha-ketoglutarate (Isocitrate dehydrogenase)

Answer

Succinyl-CoA to Succinate (Succinyl-CoA synthetase)

Answer

Acetyl-CoA + Oxaloacetate to Citrate (Citrate synthase)

Answer

Alpha-ketoglutarate to Succinyl-CoA (Alpha-ketoglutarate dehydrogenase complex)

Question 2

Which of the following statements is correct regarding the given graph?

Accepted Answer

Drug 1 represents agonist and drug 4 represents inverse agonist

Answer

Drug 1 represents agonist and drug 2 represents inverse agonist

Answer

Drug 3 represents agonist and drug 4 represents inverse agonist

Answer

Drug 2 represents partial agonist and drug 3 represents inverse agonist

Question 3

Km of an enzyme is

Accepted Answer

The substrate concentration at half maximum velocity

Answer

Numerically identical for all isozymes that catalyze a given reaction

Answer

The normal physiological substrate concentration

Answer

Dissociation constant

Question 4

Identify the type of inhibition exhibited by A?

Accepted Answer

Competitive inhibition

Answer

Uncompetitive inhibition

Answer

Mixed inhibition

Answer

Non competitive inhibition

Answer

Allosteric inhibition

Question 5

Which of the following statements best describes the mechanism of action of insulin on target cells?

Accepted Answer

Insulin binds to a transmembrane receptor on the outer surface of the plasma membrane, activating the tyrosine kinase in the cytosolic domain of the receptor.

Answer

Insulin binds to a receptor on the outer surface of the plasma membrane, activating adenylate cyclase through the Gs protein.

Answer

Insulin binds to a cytoplasmic receptor and is transferred as a hormone receptor complex to the nucleus to modulate gene expression.

Answer

Insulin enters the cell and causes the release of calcium ions from intracellular stores.

Question 6

Kcat/Km is a measure of which of the following?

Accepted Answer

Enzyme efficiency

Answer

Speed of enzymatic reaction

Answer

Concentration of substrate

Answer

Enzyme turnover

Question 7

Km increases, but Vmax remains same. This is which type of inhibition?

Accepted Answer

Competitive

Answer

Uncompetitive

Answer

Non-competitive

Answer

Irreversible

Question 8

Which of the following statements about isozymes is true?

Accepted Answer

They catalyze the same reaction but may differ in structure.

Answer

They have the same quaternary structure.

Answer

They have the same enzyme classification but differ in number and name.

Answer

They are distributed uniformly across different organs.

Question 9

What is the specific activity of an enzyme?

Accepted Answer

Enzyme units per mg of protein

Answer

Concentration of substrate transformed per minute

Answer

Enzyme units per mg of substrate

Answer

Limit of enzyme per gram of substrate

Question 10

Which kinetic parameter is primarily associated with enzyme specificity?

Accepted Answer

None of the options

Answer

Both

Answer

Km

Answer

Vmax

Enzyme Kinetics and Michaelis-Menten Equation — MCQs

Enzyme Kinetics and Michaelis-Menten Equation — MCQs

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