Question

1. Is it reasonable to say that enzymes lower the energy of the transition state for a reaction?

Yes. Like other catalysts, enzymes speed up reactions by lowering the activation energy, which is the energy of the transition state.

No. Since enzymes change pathways of reactions, we cannot say that they lower the energy of the transition state.

2. Why is the reaction faster when the liver is ground up?

Grinding speeds up the reaction of formation of catalase in the liver.

Grinding increases the solubility of catalase.

Grinding increases the surface area.

Grinding allows for more catalase to be extracted from the liver to the solution.

3. Energy profile for conversion of methyl isonitrile (H3CNC) to its isomer acetonitrile (H3CCN). How does the energy needed to overcome the energy barrier compare with the overall change in energy for this reaction?

The magnitude of energy needed to overcome the energy barrier is about the same as the magnitude of the energy change in the reaction.

The magnitude of energy needed to overcome the energy barrier is lower than the magnitude of the energy change in the reaction.

The magnitude of energy needed to overcome the energy barrier is greater than the magnitude of the energy change in the reaction.

Answer 1

1) Answer: Yes. Like other catalysts, enzymes speed up reactions by lowering the activation energy, which is the energy of the transition state.

Reason: Enzymes and catalysts both affect the rate of a reaction. In fact, all known enzymes are catalysts, but not all catalysts are enzymes. The difference between catalysts and enzymes is that enzymes are largely organic in nature and are bio-catalysts, while non-enzymatic catalysts can be inorganic compounds. Neither catalysts nor enzymes are consumed in the reactions they catalyze.

2) Answer: Grinding increases the surface area.

Reason: Grinding increases the surface area which increases the number of free sites available on the enzyme for the reaction to take place.

3) The magnitude of energy needed to overcome the energy barrier is about the same as the magnitude of the energy change in the reaction.
Reason: Not much data to explain the reason. Comment with some more information on question 3 for reasons. Will be happy to explain