Effect of increased substrate concentration on enzyme activity:
- A. Decrease the rate of reaction
- B. Increase the reaction rate until all active sites are saturated
- C. Have no effect on the reaction rate
- D. Increase the rate of reaction in a straight diagonal line
Explanation
Rate rises steeply at first because more collisions occur between substrate and free active sites, then levels off at Vmax once every site is occupied and the enzyme is working as fast as it can. The curve is therefore hyperbolic rather than a straight line, which is what the fourth option gets wrong. Beyond saturation the enzyme concentration rather than the substrate is limiting.
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