Question

Pasteur succeeded in disproving the spontaneous generation theory because

• A. He was lucky.
• B. He was ingenious in drawing out the neck of glass flasks, so as to provide access to air but not to microorganisms.
• C. Of the fact that sample of yeast taken by him was dead.
• D. Of the clear surrounding of his laboratory.

Answer 1

The correct option is B He was ingenious in drawing out the neck of glass flasks, so as to provide access to air but not to microorganisms.

Louis Pasteur used a flask whose neck was shaped like an S or the neck of a swan, hence the name "Swan Neck Flask." He put a nutrient rich broth in the flask and then boiled the broth to kill any other microorganisms which were already present. Then he allowed the broth to settle. Because of the shape of the flask, the infusion was exposed to air. However, dust particles and other things in the air never made it into the infusion. Because they were trapped in the curve of the Swan Neck Flask. No matter how long he allowed the flask to sit, microorganisms never appeared in the broth. However, if he tipped the flask and allowed the things trapped in the neck to get into the broth then microorganisms began to appear in the infusion and multiply rapidly. This demonstrates that microorganisms do not appear as a result of Spontaneous Generation. Instead, they are introduced into food through dust particles and other things that happen to land on the food. Thus, the correct answer is option B.