Question

Pasteur's experiments and similar ones that followed, convinced most people that spontaneous generation of life did not happen because

• A. Pasteur was extremely meticulous.
• B. Pasteur used very fine mesh screens to cover his flasks.
• C. Pasteur did not boil his flasks for a long time.
• D. Pasteur's swan-necked flasks ruled out the objection that spoiled air could have contaminated his experiments.

Answer 1

Answer: (D)

Pasteur's swan-necked flasks ruled out the objection that spoiled air could have contaminated his experiments.

Louis Pasteur,a French scientist who is known as the father of immunology, disproved the theory of spontaneous generation by performing a well designed experiment known as swan-necked flask experiment. He performed the experiment by taking a S- shaped neck flask along with some broth. He sterilized the broth and as the broth cooled, a puddle of condensing water was formed on the S- shape part of flask and effectively sealed it. Therefore, no microorganism could grew on the broth even though the broth was in contact with the environment. But, after the swan neck was broken, colonies of microorganisms grew on the broth.

So Pasteur concluded that growth of microorganisms was not spontaneous and was possible only if the seal was broken.

Hence, the growth of microorganisms was possible when there was contamination from the air.

So, the correct answer is D.