Some of the bacterial products listed in Tables 1 and 2 are injected into people to treat diseases. Answers to questions for Activity 1 1. Carbon dioxide produced by the yeast 2. The yeast do require nitrogen and should grow better with some protein in the broth. Yeast grow better in the presence of oxygen because they can completely oxidize the sugar.
Complete oxidation provides more energy from the sugar molecules.
The yeast should not ferment the sugar in the presence of oxygen. This is not true. Answers to questions for Activity 3 1. The aerated flask should grow best. As the bacteria grew they started using the sugar for fermentation creating acids.