Moderate

The Lock and Key Model for enzyme action proposed by Emil Fischer suggests that:

Correct answer: C. Enzymes are restricted to one reaction type.

  • A. Enzymes are unbiased for the substrate.
  • B. Enzymes can modify their active sites.
  • C. Enzymes are restricted to one reaction type.
  • D. An enzyme can catalyze a variety of reactions.

Explanation

Emil Fischer (1890) proposed a Lock and Key model to visualize substrate and enzyme interaction. According to this model, as one specific key can open only a specific lock, in the same manner, a specific enzyme can transform only one substrate into products(s). According to the Lock and Key Model, the active site is a rigid structure. There is no modification or flexibility in the active site before, during, or after the enzyme action, and it is used only as a template. Later studies did not support this model in all reactions.

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About Enzymes

Enzymes are biological catalysts that lower activation energy without being consumed, and their specificity is explained by the lock and key and induced fit models. Work includes the effects of temperature, pH and substrate concentration on reaction rate, plus competitive and non-competitive inhibition and how these differ.

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