What would happen to your cells if they made a poisonous chemical? You might think that they would die. Interestingly enough, your cells are always making poisonous chemicals, and not dying. This is because your cells use proteins known as enzymes to speed up the conversion of these poisonous chemicals into harmless ones that are useful.

According to the rule of complementary binding, all of the enzymes in your body are responsible for one
specific chemical reaction. In this lab, you will investigate an enzyme called catalase (KAT-uhLAYSS). It is
responsible for breaking down hydrogen peroxide. When hydrogen peroxide accumulates inside cells, it becomes extremely poisonous and could result in cell death. Therefore, cells rely on catalase to convert hydrogen peroxide into nontoxic molecules, such as water and oxygen.

Different living things have different amounts of catalase in their cells. You can determine the relative amount of catalase present by measuring the cells’ rates of reaction when they come into contact with peroxide. A rate of reaction is how fast a chemical reaction occurs. Since enzymes speed up chemical reactions, a fast reaction rate would mean there is a lot of catalase present. Key characteristics of a fast reaction rate are lots of bubbles, foam, and cloudiness.

Enzymes stop working when they are placed in extreme conditions outside of their optimum range, such as extreme heat. This is known as denaturation. Denaturation changes the shape of the enzyme’s active site, meaning the enzyme and substrate no longer complement one another. As a result, binding does not occur and the chemical reaction will not take place. Hence, a reaction rate of 0.