AP BIOLOGY

Detailed explanation-1: -Louis Pasteur is credited with conclusively disproving the theory of spontaneous generation with his famous swan-neck flask experiment. He subsequently proposed that “life only comes from life.”

Detailed explanation-2: -Louis Pasteur’s pasteurization experiment illustrates the fact that the spoilage of liquid was caused by particles in the air rather than the air itself. These experiments were important pieces of evidence supporting the idea of germ theory of disease.

Detailed explanation-3: -Why did Pasteur design swan-necked flasks in his experiments on spontaneous generation? The neck excluded oxygen from entering the flask. The neck stopped microorganisms in the air from contaminating the contents of the flask.

Detailed explanation-4: -Louis Pasteur’s 1859 experiment showed that a boiled nutrient broth did not give rise spontaneously to new life, but that if direct access to air was permitted, the broth decomposed, implying that small organisms (in modern terms, microbial spores) had fallen in and started to grow in the broth.

Detailed explanation-5: -Pasteur used swan neck flasks which allowed air to enter but not dust and microbes.