Antibiotics are medicines that treat infections caused by bacteria. They matter because harmful bacteria can multiply quickly and damage tissues, leading to illnesses such as strep throat, some ear infections, and certain pneumonias. Antibiotics help the immune system by slowing bacteria down or killing them directly.
They do not treat viral infections like colds, flu, or most sore throats because viruses are built differently from bacteria.
Key Facts
- Antibiotics work against bacteria, not viruses.
- Some antibiotics kill bacteria, while others stop bacteria from growing and reproducing.
- Cell wall targeting antibiotics weaken the bacterial wall so the cell can burst.
- Protein synthesis inhibitors block bacterial ribosomes, stopping bacteria from making proteins they need.
- DNA or RNA targeting antibiotics interfere with copying genetic information, which prevents bacterial reproduction.
- Finishing the prescribed course helps reduce the chance that surviving bacteria become resistant.
Vocabulary
- Antibiotic
- An antibiotic is a medicine used to kill bacteria or stop them from growing.
- Bacterium
- A bacterium is a single-celled living organism that can reproduce on its own and may sometimes cause infection.
- Virus
- A virus is a tiny infectious particle that must use a host cell to make copies of itself.
- Ribosome
- A ribosome is a cell structure that builds proteins using genetic instructions.
- Antibiotic resistance
- Antibiotic resistance happens when bacteria survive medicines that once killed them or stopped their growth.
Common Mistakes to Avoid
- Taking antibiotics for a cold or flu is wrong because these illnesses are usually caused by viruses, and antibiotics do not kill viruses.
- Stopping antibiotics as soon as you feel better is wrong because some bacteria may still be alive and can multiply again.
- Sharing leftover antibiotics is wrong because the medicine, dose, or length of treatment may not match another person’s infection.
- Skipping doses is wrong because low medicine levels may fail to control bacteria and can encourage resistant bacteria to survive.
Practice Questions
- 1 A patient must take 1 antibiotic pill every 8 hours for 7 days. How many pills are needed for the full course?
- 2 A bacterial population doubles every 30 minutes. If there are 500 bacteria at the start, how many bacteria would there be after 2 hours without treatment?
- 3 A student has a runny nose, cough, and fever from a confirmed flu infection. Explain why an antibiotic would not directly cure the infection, and name one healthy habit that can help prevent spreading it.