[Solved] Which of the following statements is true regarding enzymes?

1. All require a coenzyme for their activity.
2. All are active at neutral pH.
3. All require a molecule of water for their activity.
4. All lower the energy of activation.

Answer (Detailed Solution Below)

Option 4 : All lower the energy of activation.

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10 Questions 40 Marks 10 Mins

Concept:

• Enzymes are protein molecules that act as biological catalysts.
• They help in increasing the rate of chemical reactions that take place in living beings.

Explanation:

• All require a coenzyme for their activity: NOT TRUE
  • ​Coenzymes are non-protein, organic molecules that can bind to enzymes to enhance or facilitate the enzyme activity.
  • They are usually vitamins or vitamin derivatives.
  • ​But not all enzymes require coenzymes to function.
• All are active at neutral pH: NOT TRUE
  • ​The optimum pH of an enzyme depends on the location where it functions.
  • For example, stomach enzymes function in acidic pH, while in small intestine enzymes function in a slightly basic pH.
  • Therefore, all enzyme activity do not occur at neutral pH.
• All require a molecule of water for their activity: NOT TRUE
  • ​Enzyme activity has been found to be enhanced in the presence of water.
  • However, enzymes may still be functional in the absence of water.
• All lower the energy of activation: TRUE
  • ​Enzymes increase the rate of reaction by lowering the activation energy.
  • Activation energy is the minimum amount of energy required to activate atoms or molecules so that they can undergo chemical transformations in a reaction.
  • The lower the activation energy, the faster will be the reaction catalyzed by an enzyme.