Questions: Germs: Bacteria and Viruses

Question 1

A student has the flu and asks their doctor for antibiotics. Why would a good doctor refuse this request?

• A. Antibiotics are too expensive for the flu
• B. The flu is caused by a virus, and antibiotics only work against bacteria
• C. Doctors prefer to let all illnesses heal naturally
• D. Antibiotics would make the flu worse

Answer: (B)

Influenza (flu) is caused by a virus. Antibiotics are designed to kill or inhibit bacteria by targeting structures (like cell walls) that bacteria have but viruses lack. Since viruses are fundamentally different from bacteria -- they're not even technically alive -- antibiotics have no effect on them. Prescribing antibiotics for viral infections is not just useless; it contributes to antibiotic resistance, making bacterial infections harder to treat in the future.

Question 2

Most bacteria are germs that make you sick.

• T. True
• F. False

Answer: False

Only a small percentage of bacteria species cause disease in humans. Your body contains trillions of beneficial bacteria, especially in your digestive system (gut flora), that help you digest food, produce vitamins, and crowd out harmful bacteria. Bacteria are also used to make yogurt, cheese, and certain medicines. The word 'germ' specifically refers to microorganisms that cause disease, and most bacteria do not qualify.

Question 3

Explain two key differences between bacteria and viruses.

Model answer: 1) Bacteria are living, single-celled organisms that can reproduce on their own, while viruses are not technically alive and can only reproduce by invading a living cell and hijacking its machinery. 2) Bacteria are much larger than viruses. 3) Bacterial infections can be treated with antibiotics, while viral infections cannot.

These differences have practical importance. Because bacteria are living cells with their own structures (cell walls, ribosomes), antibiotics can target those structures to kill the bacteria. Viruses lack these structures -- they're just genetic material in a protein shell -- so antibiotics have nothing to target. This is why the bacterial vs. viral distinction matters beyond academic biology: it determines what treatment will actually work.