Homeostasis of Enzymes What is an enzyme? How do enzymes work? What factors can effect enzyme action?

Enzyme --An enzyme is a biological catalyst (They speed the rate of chemical reactions) --Increase the rate of reaction by lowering the amount of activation energy --They are responsible for thousands and thousands of chemical processes that sustain life --Enzymes are proteins in nature and structure

Enzyme Action Enzymes act by converting starting molecules (substrates) into different molecules (products) Almost all chemical reactions in a biological cell need enzymes in order to occur at rates sufficient for life If it doesn’t happen fast enough, cell death could result

Organization Remember: If cells die, tissues are compromised If tissues are compromised, organs can fail If organs fail, systems won’t function If systems won’t function, Humans can die

Factors affecting the rate of enzyme activity Optimum is a useful word which means "the best” We call the temperature or pH which makes an enzyme work at its very fastest the optimum for that enzyme The rate of enzyme activity increases with as temperature increases until the optimum temperature, then falls to zero as the enzyme is denatured

Denatured….. This means that the protein changes shape and the active site is no longer complementary to the substrate molecule

Graphing the action of enzymes

Enzyme: Catalase In your body, the enzyme catalase is very important. I helps to convert Hydrogen Peroxide to Oxygen and Water Take a look at the following graph:

In the graph, the rate of catalase activity is directly related to the percent increase in Oxygen

What can you can conclude from the graph?