Final answer:
An antibiotic is a substance that inhibits or kills bacteria and can originate from natural sources or be synthetically made. It plays a crucial role in treating bacterial infections, but improper use has led to antibiotic resistance and a global healthcare crisis.
Step-by-step explanation:
To define key terms: an antibiotic is a chemical substance that has the ability to inhibit or destroy the growth of bacteria and other microorganisms. This term originates from the Greek 'anti' meaning 'against' and 'bios' meaning 'life.'
Antibiotics can be naturally produced by organisms such as fungi or bacteria, or they can be synthetically manufactured. These substances work by targeting various essential enzymes and processes needed for the survival and reproduction of bacteria.
There's a growing concern about antibiotic resistance, which is the ability of bacteria to withstand the effects of an antibiotic, leading to a global health challenge known as the antibiotic crisis. An antibiotic does not specifically act against viruses; viral infections require antiviral medications. It's crucial to use antibiotics responsibly to lessen the risk of developing resistant strains of bacteria.