Bacterial Diseases
Get to grips with Bacterial Diseases for GCSE Biology with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. Salmonella and gonorrhoea are the required bacterial examples — know how each one is spread and controlled.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Two bacterial diseases are required: salmonella food poisoning and gonorrhoea.
Salmonella is spread by eating food contaminated with the bacteria, either food prepared in unhygienic conditions or poultry infected before slaughter. The bacteria produce toxins causing fever, abdominal cramps, vomiting and diarrhoea. In the UK, poultry are vaccinated against salmonella to control the spread.
Gonorrhoea is a sexually transmitted disease. Symptoms include a thick yellow or green discharge and pain on urinating. It was once easily treated with penicillin, but many resistant strains have appeared, so it is now treated with other antibiotics. Spread is controlled by treatment and by using barrier methods of contraception such as condoms.
Revision notes
Salmonella
Spread by eating contaminated food — either food prepared unhygienically or poultry infected before slaughter.
The bacteria produce toxins causing fever, abdominal cramps, vomiting and diarrhoea. Control: poultry are vaccinated in the UK, and food should be prepared hygienically and cooked thoroughly.
Gonorrhoea
A sexually transmitted disease spread by sexual contact.
Symptoms are a thick yellow or green discharge from the penis or vagina and pain on urinating. Control: treatment with antibiotics and use of barrier contraception such as condoms.
Antibiotic resistance
Gonorrhoea was once easily treated with penicillin, but many resistant strains have emerged.
This is a good example of why antibiotics should not be overused, and it links directly to the topic of antibiotic-resistant bacteria.
Key points
- Salmonella is spread by contaminated food.
- Salmonella bacteria produce toxins causing fever and vomiting.
- UK poultry are vaccinated against salmonella.
- Gonorrhoea is a sexually transmitted disease.
- Gonorrhoea causes discharge and pain on urinating.
- Resistant strains mean penicillin is no longer effective.
Worked examples
Example 1
Describe how salmonella food poisoning is spread and how the spread is controlled in the UK. [3 marks]
Model answer
It is spread by eating food contaminated with salmonella bacteria, either prepared unhygienically or from poultry infected before slaughter (2 marks). In the UK, poultry are vaccinated against salmonella to control the spread (1 mark).
Example 2
Give two ways the spread of gonorrhoea can be reduced. [2 marks]
Model answer
Treating infected people with antibiotics so they cannot pass it on (1 mark), and using barrier methods of contraception such as condoms during sexual contact (1 mark).
Example 3
Explain why penicillin is no longer used to treat gonorrhoea. [2 marks]
Model answer
Many strains of the bacterium have become resistant to penicillin (1 mark), so the antibiotic no longer kills them and a different antibiotic must be used (1 mark).
Common mistakes
Saying salmonella is a virus.
It is a bacterium, and it produces toxins.
Forgetting the vaccination of poultry.
It is the specific UK control measure and is frequently examined.
Saying gonorrhoea cannot be treated.
It can, but with antibiotics other than penicillin because of resistance.
Giving only one control method.
Questions usually want both treatment and prevention.
Exam tips
- Learn the specific control measure for each disease.
- Say bacteria produce toxins when explaining symptoms.
- Use gonorrhoea as your example when discussing antibiotic resistance.
- Give both treatment and prevention when asked how spread is reduced.
Key terms
- Salmonella
- A bacterium causing food poisoning.
- Gonorrhoea
- A sexually transmitted bacterial disease.
- Barrier method
- Contraception such as a condom that prevents contact.
- Resistant strain
- A population of bacteria unaffected by a particular antibiotic.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.