2.61: Exercise 22.1
- Page ID
- 94744
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Answers
- Did this bacterial species produce gas? Yes
- Did this bacterial species produce acid? Yes
- Did fermentation occur? Yes
Solution
- Gas was produced. The upside-down tiny tube inside the test tube (the Durham tube) is not completely filled with liquid medium. It has some gas in it. This indicates the bacterial species produced gas during fermentation and it was trapped inside of the Durham tube.
- Acid was produced. The medium is yellow. When the medium was inoculated it was red. When the pH of this medium becomes acidic, a pH indicator will change from red to yellow. Since the medium is yellow, it indicates that acid was produced to reduce the pH.
- Fermentation occurred. If either acid or gas is produced or if acid and gas are produced then fermentation has occurred.