Question

Alexander Fleming had been running tests using Staphylococcus, and he left some plates out to incubate. Evidently, after returning to his lab after the weekend, he found that Penicillium mold was growing on his agar plates containing the growth of Staphylococcus. Looking more closely, he found a large, clear area around the mold colony where Staphylococcus colonies did not grow. Given this situation, a valid hypothesis would be that:A.The Staphylococcus was being inhibited by the Penicillium mold.B. The Penicillium mold was being killed by the Staphylococcus.C. The bacteriological medium being used in the plates was somehow inhibitory to the Staphylococcus growth.D. The room temperature incubation was inhibitory to the growth of Staphylococcus.

Answer 1

A. The Staphylococcus was being inhibited by the Penicillium mold.

Step-by-step explanation:

The large, clear area around the mold colony indicated that the Staphylococcus was not growing near the mold, therefore Fleming concluded that the mold was producing something that inhibited the bacteria from growing. Upon further testing he found that the Penicillium mold was able to keep the bacteria away to prevent competition for resources by producing a chemical which he called penicillin which was the first antibiotic known to man. A great discovery which granted Fleming the Nobel prize in Medicine in 1945.