AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
Antibiotics and painkillers: Antibiotics cannot kill viral pathogens.
Antibiotics work by interfering with structures or processes found in bacteria, such as bacterial cell walls or bacterial protein synthesis.
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Antibiotics work by interfering with structures or processes found in bacteria, such as bacterial cell walls or bacterial protein synthesis. Viruses are not cells; they are much smaller and reproduce only inside host cells. They have no bacterial cell wall and no bacterial metabolism for an antibiotic to target, so antibiotics cannot kill viral pathogens. This is why antibiotics do not cure viral infections such as influenza, the common cold or measles. Viral infections may be treated with antivirals, and vaccination can prevent them. Painkillers relieve symptoms but do not kill pathogens. Understanding this difference helps explain why antibiotics should not be prescribed for viral illnesses.
What earns the marks
- Antibiotics kill bacteria by targeting bacterial structures or processes.
- Viruses are not cells and lack the bacterial targets that antibiotics act on.
- Therefore antibiotics cannot kill viral pathogens.
- Viral infections such as influenza or the common cold are not cured by antibiotics.
- Antivirals and vaccines, not antibiotics, are used against viral pathogens.
Common mistakes and how to put them right
Claiming antibiotics can treat flu or the common cold.
Put it right by stating that these are viral and antibiotics do not kill viruses.
Confusing painkillers with antibiotics.
Put it right by saying painkillers relieve symptoms but do not kill pathogens.
Thinking antibiotics work against all pathogens.
Put it right by specifying that they act on bacteria only.
Exam tips
- Contrast bacteria and viruses in one sentence to show why antibiotics fail against viruses.
- Name a viral infection to support your answer.
- Mention that antivirals or vaccines are used for viral infections.
Try the lesson
The start of the Antibiotics and painkillers: Antibiotics cannot kill viral pathogens. lesson, made from checked teaching notes for this specification point.
Have a go first
A doctor explains to a patient that antibiotics will not cure their cold. What is the biological reason for this?
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Key words
Say what each word means before you turn the card.
Antibiotics
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Viruses
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Antivirals
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Vaccination
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See every definition
- Antibiotics
- Substances that work by interfering with structures or processes found in bacteria, such as bacterial cell walls or bacterial protein synthesis.
- Viruses
- Non-cellular pathogens that are much smaller than cells and reproduce only inside host cells.
- Antivirals
- Medicines that may be used to treat viral infections.
- Vaccination
- A way of preventing viral infections.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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