Enzymes and Kinetics – Section 2

6. For an enzyme that displays Michaelis-Menten kinetics, the reaction velocity (as a fraction of Vmax ) observed at [S] = 2 KM will be

A. 0.09
B. 0.33
C. 0.66
D. 0.91

Correct Answer: C. 0.66

7. Predominantly uncompetitive inhibition may be called when

A. competitive inhibition is greater than uncompetitive inhibition
B. competitive inhibition is smaller than uncompetitive inhibition
C. competitive inhibition is equal to uncompetitive inhibition
D. none of the above

Correct Answer: A. competitive inhibition is greater than uncompetitive inhibition

8. An enzyme has a Km of 4.7 x 10-5M. If the Vmax of the preparation is 22m moles liter-1 min-1, what velocity would be observed in the presence of 2.0 x 10-4M substrate and 5.0 x 10-5M of a competitive inhibitor?

A. 13.54μ moles liter-1min-1
B. 6.68μ moles liter-1min-1
C. 7.57μ moles liter-1min-1
D. 17.8μ moles liter-1min-1

Correct Answer: A. 13.54μ moles liter-1min-1

9. The rate equation in non-competitive inhibition based on Michaelis Menten equation is given by

A. rmaxS/(Km + S)(1+I/Ki)
B. rmaxE/(Km (1+I/Ki)+S))
C. VmaxS/(Km + S)(1+I/Ki)
D. rmaxS/Km

Correct Answer: A. rmaxS/(Km + S)(1+I/Ki)

10. Which of the following statement(s) regarding enzymes, is/are false?

A. Enzymes are always proteins that function as catalysts
B. Enzymes provide activation energy for reactions
C. Enzyme activity can be regulated
D. Enzymes may be used many times for a specific reaction

Correct Answer: B. Enzymes provide activation energy for reactions

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