What do we call a chemical substance derived from mold or bacteria that is used to kill microorganisms?

The term used to describe a chemical substance derived from mold or bacteria that is used to kill microorganisms is "antibiotic." Antibiotics are compounds that can effectively inhibit the growth of bacteria or destroy them. They are particularly significant in treating bacterial infections in humans and animals.

The historical discovery of penicillin, an antibiotic derived from the mold Penicillium, marked a significant advancement in medical science. Antibiotics work by targeting specific bacterial processes or structures, which allows them to eliminate harmful bacteria while causing minimal harm to the host's cells.

In contrast, antiseptics are typically used externally to prevent infection in wounds and do not necessarily originate from natural substances like molds or bacteria. Analgesics are pain-relieving medications and do not directly target microorganisms. Hormones are signaling molecules produced by glands that regulate various physiological processes in the body and have no relation to the killing of microorganisms.