AP BIOLOGY

Detailed explanation-1: -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-2: -Straining the reactants and bringing them close together are two common ways the enzymes use to lower the activation energy. There are other methods that the enzymes use to facilitate a chemical reaction.

Detailed explanation-3: -The answer is enzymes. Enzymes in our bodies are catalysts that speed up reactions by helping to lower the activation energy needed to start a reaction.

Detailed explanation-4: -Enzymes (and other catalysts) act by reducing the activation energy, thereby increasing the rate of reaction.

Detailed explanation-5: -A catalyst lowers the activation energy by changing the transition state of the reaction. The reaction then goes through a different pathway/mechanism than the uncatalyzed reaction. The catalyst does not change the net energy difference between reactant and product.