Chapter 1, Problem 2S

The classic experiment by Pasteur (figure 1.4) tested the hypothesis that cells arise from other cells. In this experiment cell growth was measured following sterilization of broth in a swan-necked flask or in a flask with a broken neck.

a. Which variables were kept the same in these two experiments?

b. How does the shape of the flask affect the experiment?

c. Predict the outcome of each experiment based on the two hypotheses.

d. Some bacteria (germs) are capable of producing heat-resistant spores that protect the cell and allow it to continue to grow after the environment cools. How would the outcome of this experiment have been affected if spore-forming bacteria were present in the broth?