5.5 summary

To start a chemical reaction, one needs to weaken the chemical bonds found in the reactants. This process requires that the molecules be able to absorb energy and it is known as activation energy. One way to weaken the chemical bonds is to heat it up, some cellular reactions use something known as catalysts, which speed up the chemical reaction. The main catalysts of chemical reactions are known as enzymes which are specialized proteins. An enzyme catalyzes only one type of reaction by specific reactions only allow enzyme of a certain shape and a specific reactant acted upon by an enzyme is called the enzyme's substrate. The substrate only fits into a certain region of an enzyme known as the active site.



Concept Check
1. Explain the role of activation energy in a reaction. How does an enzyme affect activation energy? The role of activation energy in a reaction is that this is the initial energy with which a reaction starts. This energy activates reactants to start a chemical reaction. An enzyme lowers the activation energy, thus speeding up the chemical reaction.
2. Describe how a subtrate interacts with an enyzme. A subtrate interacts with an enzyme by entering the active site of the enzyme. The fit between the subtrate and the enzyme is not rigid, but instead the enzyme's active sight slightly changes shape to fit the subtrate.88