GCSE Biology revision

Antibiotics and painkillers

Communicable diseases

AQA 4.1.1.1

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AQA student objectives

Learning pathway

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ALL 🎯

Identify and describe What Are Antibiotics?, The Discovery of Penicillin and Examples of Antibiotics in the context of antibiotics and painkillers.

MOST 🎯🎯

Explain the relationships between What Are Antibiotics?, The Discovery of Penicillin and Examples of Antibiotics and how they contribute to antibiotics and painkillers.

SOME 🎯🎯🎯

Apply and analyse knowledge of What Are Antibiotics?, The Discovery of Penicillin and Examples of Antibiotics to interpret unfamiliar information about antibiotics and painkillers.

Revision summary

Key knowledge

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What Are Antibiotics?

Antibiotics are a type of medication, typically taken in tablet form, used to treat bacterial diseases such as salmonella and gonorrhoea.
Antibiotics cannot be used to treat viral, fungal, or protist diseases — only bacterial infections.
Antibiotics treat existing bacterial infections but cannot prevent diseases; vaccines are an example of preventative medicine instead.

1. What Are Antibiotics?AQA

Notes

Antibiotics are a type of medication, typically taken in tablet form, used to treat bacterial diseases such as salmonella and gonorrhoea.
Antibiotics cannot be used to treat viral, fungal, or protist diseases — only bacterial infections.
Antibiotics treat existing bacterial infections but cannot prevent diseases; vaccines are an example of preventative medicine instead.

The Discovery of Penicillin

Alexander Fleming discovered penicillin in 1928 when he returned from holiday to find his petri dish of Staphylococcus aureus bacteria contaminated with mould.
Fleming noticed the mould was producing a chemical that destroyed the surrounding bacteria, leading him to recognise its potential as a medicine.
This chemical, derived from the mould Penicillium, became the basis for the first antibiotic, revolutionising the treatment of bacterial diseases.
In his Nobel Prize speech, Fleming warned that misuse of antibiotics could lead to devastating consequences, including antibiotic resistance.

2. The Discovery of PenicillinAQA

Notes

Alexander Fleming discovered penicillin in 1928 when he returned from holiday to find his petri dish of Staphylococcus aureus bacteria contaminated with mould.
Fleming noticed the mould was producing a chemical that destroyed the surrounding bacteria, leading him to recognise its potential as a medicine.
This chemical, derived from the mould Penicillium, became the basis for the first antibiotic, revolutionising the treatment of bacterial diseases.
In his Nobel Prize speech, Fleming warned that misuse of antibiotics could lead to devastating consequences, including antibiotic resistance.

Examples of Antibiotics

Penicillin was the first antibiotic to be discovered and remains one of the most well-known examples.
Other commonly used antibiotics include amoxicillin and erythromycin, though some patients can be allergic to certain types.

How Bacteria Develop Antibiotic Resistance

Bacteria reproduce rapidly through binary fission, meaning generations are much shorter than in humans, allowing mutations to spread quickly.
Beneficial mutations in a bacterium's genome can allow it to survive exposure to antibiotics, making it resistant.
Bacteria also carry plasmids — small, extra loops of DNA in the cytoplasm — which can contain antibiotic resistance genes.
Resistant bacteria, sometimes called superbugs, cannot be destroyed by standard antibiotics, making them very difficult to treat.
MRSA (Methicillin-resistant Staphylococcus aureus) is a well-known example of a superbug that poses serious challenges in healthcare settings.

4. How Bacteria Develop Antibiotic ResistanceAQA

Notes

Bacteria reproduce rapidly through binary fission, meaning generations are much shorter than in humans, allowing mutations to spread quickly.
Beneficial mutations in a bacterium's genome can allow it to survive exposure to antibiotics, making it resistant.
Bacteria also carry plasmids — small, extra loops of DNA in the cytoplasm — which can contain antibiotic resistance genes.
Resistant bacteria, sometimes called superbugs, cannot be destroyed by standard antibiotics, making them very difficult to treat.
MRSA (Methicillin-resistant Staphylococcus aureus) is a well-known example of a superbug that poses serious challenges in healthcare settings.

Causes of Antibiotic Resistance

Not completing a full course of antibiotics gives bacteria exposure to low levels of the drug, allowing them to adapt and become resistant.
Using antibiotics to treat non-bacterial diseases, such as viral infections, contributes unnecessarily to the development of resistance.
The overuse of antibiotics in farming and agriculture — given to livestock to prevent disease — is a major contributor to increasing antibiotic resistance globally.
Antibiotic resistance is increasing in prevalence worldwide, largely due to the historical and ongoing misuse of these medicines.

5. Causes of Antibiotic ResistanceAQA

Notes

Not completing a full course of antibiotics gives bacteria exposure to low levels of the drug, allowing them to adapt and become resistant.
Using antibiotics to treat non-bacterial diseases, such as viral infections, contributes unnecessarily to the development of resistance.
The overuse of antibiotics in farming and agriculture — given to livestock to prevent disease — is a major contributor to increasing antibiotic resistance globally.
Antibiotic resistance is increasing in prevalence worldwide, largely due to the historical and ongoing misuse of these medicines.

Why Antibiotics Don't Work on Viruses

Viruses are non-living and rely on a host cell to replicate, meaning they do not have the same cellular structures that antibiotics target in bacteria.
Because antibiotics work by targeting bacterial cells specifically, they have no effect on viral pathogens.

What Are Painkillers?

Painkillers are a different type of medication to antibiotics and are used to alleviate the symptoms of pain caused by disease.
Unlike antibiotics, painkillers can be used for a range of diseases regardless of whether they are caused by bacteria, viruses, or other pathogens.
Painkillers do not cure diseases — they only relieve symptoms such as pain, which is often caused by toxins produced by pathogens.
Common examples of painkillers include paracetamol and aspirin.

7. What Are Painkillers?AQA

Notes

Painkillers are a different type of medication to antibiotics and are used to alleviate the symptoms of pain caused by disease.
Unlike antibiotics, painkillers can be used for a range of diseases regardless of whether they are caused by bacteria, viruses, or other pathogens.
Painkillers do not cure diseases — they only relieve symptoms such as pain, which is often caused by toxins produced by pathogens.
Common examples of painkillers include paracetamol and aspirin.

Antibiotics vs Painkillers: Key Differences

Antibiotics actively destroy or inhibit the growth of bacteria, addressing the cause of a bacterial infection directly.
Painkillers only manage symptoms such as pain and do not target or eliminate the pathogen causing the disease.
Antibiotics are specific to bacterial diseases, whereas painkillers can provide symptom relief across a wider range of conditions.

8. Antibiotics vs Painkillers: Key DifferencesAQA

Notes

Antibiotics actively destroy or inhibit the growth of bacteria, addressing the cause of a bacterial infection directly.
Painkillers only manage symptoms such as pain and do not target or eliminate the pathogen causing the disease.
Antibiotics are specific to bacterial diseases, whereas painkillers can provide symptom relief across a wider range of conditions.

The Importance of Using Antibiotics Responsibly

Patients should always complete their full prescribed course of antibiotics, even if they begin to feel better, to prevent resistance developing.
Antibiotics should only be prescribed and taken for confirmed bacterial infections, not as a precaution or for viral illnesses.
Reducing the overuse of antibiotics in both medicine and agriculture is essential to preserving their effectiveness for future generations.

9. The Importance of Using Antibiotics ResponsiblyAQA

Notes

Patients should always complete their full prescribed course of antibiotics, even if they begin to feel better, to prevent resistance developing.
Antibiotics should only be prescribed and taken for confirmed bacterial infections, not as a precaution or for viral illnesses.
Reducing the overuse of antibiotics in both medicine and agriculture is essential to preserving their effectiveness for future generations.