Summary 5.5

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.

Images:
http://waynesword.palomar.edu/images/enzyme5.gif
(Enzyme connecting to a substrate)
http://www.accessexcellence.org/RC/VL/GG/images/enzyme.gif
(Enzyme activity)

Concept Check
Explain the role of activation energy in a reaction. How does an enzyme affect activation energy?
Activation energy is the start-up energy for a reaction. An enzyme can affect activation energy by acting as a catalysts that speed up the chemical reactions.
Describe how a substrate interacts with an enzyme.
A substrate interacts with an enzyme by the enzyme acting upon a specific reactant, and the substrate then fits into a particular location of the enzyme known as the active site.