Question

How did Pasteur's experiment with sterile broth in open flasks demonstrate the principle that cells only come from preexisting cells?

A. By demonstrating that sterile broth would not ferment in contact with air alone.
B. By demonstrating that the air contained microbes.
C. By demonstrating that broth would not ferment if sterile.
D. By demonstrating that sterile broth fermented in contact with air

Answer 1

Pasteur's experiment with swan-neck flasks proved that sterile broth only becomes contaminated when exposed to airborne microorganisms, demonstrating that cells come from preexisting cells, not spontaneous generation.

Step-by-step explanation:

Louis Pasteur's experiment with sterile broth in open flasks demonstrated the principle that cells only come from preexisting cells by showing that the sterile broth would not ferment or become contaminated when protected from airborne microbes. He used swan-neck flasks that allowed air to enter but prevented the entry of bacterial and fungal spores due to their unique design. This meant that any life force other than the airborne microorganisms had access to the broth, but since the sterilized broth remained uncontaminated until the flask’s neck was broken, it proved that microorganisms in the air, and not spontaneous generation, were responsible for contamination. The control group in Pasteur's experiment was the broth in the intact swan-neck flask, which showed that when protected from airborne contaminants, broth remained sterile, reinforcing the concept of Omne vivum ex vivo (Life only comes from life).