Which description best fits the graph of reaction rate against increasing substrate concentration at a fixed enzyme concentration?
Correct answer: B. A curve that rises and then levels off as active sites fill
- A. A straight line rising forever
- B. A curve that rises and then levels off as active sites fill
- C. A curve that falls from the start
- D. A horizontal line from the beginning
Explanation
At low substrate, rate climbs steeply with each added molecule, but once every active site are occupied the enzyme is saturated and the curve plateaus. A straight line would imply no saturation, which contradicts the finite number of active sites.
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About Characteristics of Enzymes
Enzymes are globular biological catalysts that lower activation energy without being consumed, usually showing specificity for particular substrates. Questions cover active sites, enzyme substrate complexes, the lock and key and induced fit models, intracellular and extracellular action, and the effects of denaturation, while distinguishing enzymes from non biological catalysts.
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