One day you notice that yogurt containers have the phrase, “contains active cultures.” Which of the following statements would be true regarding these anaerobic organisms in yogurt?

Question

The bacteria in yogurt undergo fermentation.
The bacteria in yogurt undergo photosynthesis.
The bacteria in yogurt are using cellular respiration.
The bacteria in yogurt are using oxygen to get energy.

Answer 1

The true statement regarding the anaerobic organisms in yogurt is:

The bacteria in yogurt undergo fermentation.

Yogurt contains live bacteria, primarily Lactobacillus and Streptococcus species, which ferment lactose (the sugar in milk) into lactic acid. This process does not require oxygen and is characteristic of fermentation. The other statements regarding photosynthesis, cellular respiration (dependent on oxygen), and using oxygen are not true in the context of the anaerobic organisms typical in yogurt.