AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
It is caused by a bacterium and was easily treated with the antibiotic…
Full specification wording
Bacterial diseases: It is caused by a bacterium and was easily treated with the antibiotic penicillin until many resistant strains appeared.
Gonorrhoea is caused by a bacterium, so it can be treated with antibiotics.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 5 of 7
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Gonorrhoea is caused by a bacterium, so it can be treated with antibiotics. Penicillin was once a very effective treatment, and most infections were cleared easily. However, bacteria reproduce rapidly and mutations can arise that make some individuals resistant to penicillin. When antibiotics are used, non-resistant bacteria are killed while resistant bacteria survive and reproduce, passing on the resistance. Over time, resistant strains become more common, so penicillin is no longer a reliable treatment for gonorrhoea. This is an example of natural selection in bacteria and shows why antibiotics should be used carefully and why new antibiotics or different treatment combinations are needed.
What earns the marks
- Gonorrhoea is caused by a bacterium, so antibiotics such as penicillin can kill the pathogen.
- Penicillin was originally an effective and easily used treatment for gonorrhoea.
- Mutations can produce bacteria that are resistant to penicillin.
- Antibiotic use selects for resistant bacteria, which survive and reproduce, so resistant strains become more common.
- Resistance means penicillin is no longer reliably effective, so alternative antibiotics or treatment combinations are needed.
Common mistakes and how to put them right
Saying the person becomes resistant to the antibiotic.
Put it right: It is the bacteria that become resistant, not the human.
Thinking resistance develops because the body gets used to the antibiotic.
Put it right: Resistance arises from random mutation followed by natural selection when the antibiotic is used.
Believing antibiotics work against all infections.
Put it right: Antibiotics kill bacteria, not viruses, and resistance can reduce their effectiveness against some bacteria.
Exam tips
- Explain resistance using the sequence: mutation, antibiotic selection, survival and reproduction of resistant bacteria.
- Avoid saying that antibiotics create mutations; mutations occur naturally and the antibiotic selects the resistant bacteria.
- Link resistance to the need for careful antibiotic use and the development of new treatments.
Try the lesson
The start of the Bacterial diseases: It is caused by a bacterium and was easily treated with the antibiotic penicillin until many resistant strains appeared. lesson, made from checked teaching notes for this specification point.
Have a go first
What type of organism causes gonorrhoea?
Listen
Gonorrhoea is caused by a bacterium, so it can be treated with antibiotics. Penicillin was once a very effective treatment, and most infections were cleared easily. However, bacteria reproduce rapidly and mutations can arise that make some individuals resistant to penicillin. When antibiotics are used, non-resistant bacteria are killed while resistant bacteria survive and reproduce, passing on the resistance. Over time, resistant strains become more common, so penicillin is no longer a reliable treatment for gonorrhoea. This is an example of natural selection in bacteria and shows why antibiotics should be used carefully and why new antibiotics or different treatment combinations are needed. A strong answer earns marks for these points. Gonorrhoea is caused by a bacterium, so antibiotics such as penicillin can kill the pathogen. Penicillin was originally an effective and easily used treatment for gonorrhoea. Mutations can produce bacteria that are resistant to penicillin. Antibiotic use selects for resistant bacteria, which survive and reproduce, so resistant strains become more common. A common slip: Saying the person becomes resistant to the antibiotic. Instead, it is the bacteria that become resistant, not the human. Exam tip: Explain resistance using the sequence: mutation, antibiotic selection, survival and reproduction of resistant bacteria.
See it
Put it in order
Put these steps in the order they happen.
- 1. Resistant bacteria survive and reproduce
- 2. Alternative antibiotics or treatment combinations needed
- 3. Resistant strains become more common
- 4. Gonorrhoea caused by a bacterium
- 5. Treated with penicillin
- 6. Penicillin no longer reliably effective
- 7. Mutations can produce resistant bacteria
- 8. Antibiotic use selects for resistant bacteria
Key words
Say what each word means before you turn the card.
Bacterial disease
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Antibiotics and treatment
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Antibiotic resistance
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Natural selection
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See every definition
- Bacterial disease
- A disease caused by a bacterium, such as gonorrhoea, which can be treated with antibiotics such as penicillin.
- Antibiotics and treatment
- Antibiotics such as penicillin can kill the pathogen, and penicillin was originally an effective and easily used treatment for gonorrhoea.
- Antibiotic resistance
- Mutations can produce bacteria that are resistant to penicillin, so it is no longer reliably effective and alternative antibiotics or treatment combinations are needed.
- Natural selection
- Antibiotic use selects for resistant bacteria, which survive and reproduce, so resistant strains become more common; this is an example of natural selection in bacteria.
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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