How marijuana affects the mind. Marijuana reaches the same pleasure centers in the brain that are targeted by heroin, cocaine and alcohol. Depending on the quantity, quality and method of consumption, marijuana can produce a feeling of euphoria â or high â by stimulating brain cells to release the chemical dopamine.
In 1928, Alexander Fleming made one of the most important contributions to the field of antibiotics. In an experiment, he found that a strain of green Penicillium mold inhibited the growth of bacteria on an agar plate. This led to the development of the first modern era antibiotic, penicillin.
Penicillin is one of the earliest discovered and widely used antibiotic agents, derived from the Penicillium mold. Antibiotics are natural substances that are released by bacteria and fungi into the their environment, as a means of inhibiting other organisms-it is chemical warfare on a microscopic scale.