AP BIOLOGY

Detailed explanation-1: -If spontaneous generation had been a real phenomenon, Pasteur argued, the broth in the curved-neck flask would have eventually become reinfected because the germs would have spontaneously generated. But the curved-neck flask never became infected, indicating that the germs could only come from other germs.

Detailed explanation-2: -In summary, Pasteur boiled a meat broth in a flask that had a long neck that curved downward, like a goose. The idea was that the bend in the neck prevented falling particles from reaching the broth, while still allowing the free flow of air.

Detailed explanation-3: -This demonstrated that certain germ particles in the air caused the spoiling of the broth, disproving spontaneous generation – a previous leading theory of disease that claimed the air itself was to blame.

Detailed explanation-4: -Louis Pasteur designed an experiment to test whether sterile nutrient broth could spontaneously generate microbial life. Each flask was then heated to boil the broth in order to make sure all existing microbes were killed.

Detailed explanation-5: -He heated an infusion sealed in a vessel with a S-shaped or “Swan neck", let it cool, and then broke of the tip of the vessel. This allowed fresh air to enter, but any particulate matter was trapped in the bend of the neck. The culture did not putrefy, even though it had access to air.