page 215, number 1 & page 216, number 2

1. Explain the toxic effect of O2 on strict anaerobes.
With the absence of synthesis catalase, peroxidase, or superoxide dimutase, the toxic concentration of H2O2 cannot be degraded when these organisms are cultivated in the absence of O2.

2. Illustrate the chemical reaction involved in the degradation of hydrogen peroxide in the presence of catalase.
2H2O2 ------> catalase ------> 2H2O + O2