Cracking the AP Biology Exam




In this lab, the rate of conversion of hydrogen peroxide (H2O2) to water and oxygen gas was measured as the enzyme catalase was added to the experiment.

What are the general concepts you really need to know?

  • This lab tested your basic understanding of enzymes. Enzymes are catalysts that accelerate specific reactions without altering the reaction itself.
  • Don’t forget that the initial reaction rates can be influenced by four things: pH, temperature, enzyme concentration, and substrate concentration.
  • Remember that a reaction can stop if the enzyme is denatured, that is, if it loses its shape.
  • If you’re asked to design an experiment to measure the effect of these four variables on enzyme activity, keep all the conditions constant except for the variable of interest. For example, to measure the effects of pH in an experiment, maintain the temperature, enzyme concentration, and substrate concentration as you change the pH.