LIFE SCIENCE

Detailed explanation-1: -The energy required to reach the transition state (the activation energy) constitutes a barrier to the progress of the reaction, limiting the rate of the reaction. Enzymes (and other catalysts) act by reducing the activation energy, thereby increasing the rate of reaction.

Detailed explanation-2: -Enzymes are biological catalysts. Catalysts lower the activation energy for reactions. The lower the activation energy for a reaction, the faster the rate. Thus enzymes speed up reactions by lowering activation energy.

Detailed explanation-3: -Enzymes allow activation energies to be lowered. Enzymes lower the activation energy necessary to transform a reactant into a product.

Detailed explanation-4: -An enzyme is a biological catalyst and is almost always a protein. It speeds up the rate of a specific chemical reaction in the cell. The enzyme is not destroyed during the reaction and is used over and over.