Question

question 4 of 10
the word antibiotic was originally defined, in 1942, as being any substance produced by a microorganism that inhibits the growth of another microorganism. how does the modern definition of antibiotic differ?
a. an antibiotic is a synthetic chemical that inhibits the growth of infectious bacteria.
b. an antibiotic is any chemical, natural or synthetic, that inhibits the growth of a microorganism.
c. an antibiotic is a chemical that damages the dna of infectious bacteria.
d. an antibiotic is any chemical that inhibits the growth of any organism, not just a microorganism.

Explanation:

The original definition in 1942 was limited to substances produced by microorganisms. The modern definition has expanded to include any chemical (whether natural or synthetic) that inhibits microorganism growth. Option A is too narrow (only synthetic and focuses on bacteria). Option C is incorrect as it's not the general modern definition. Option D is wrong as it's about microorganisms, not any organism. Option B correctly reflects the modern, broader definition.

Answer:

B. An antibiotic is any chemical, natural or synthetic, that inhibits the growth of a microorganism.