1. 1
   A garden centre worker notices purple and black spots developing on the leaves of the rose bushes in the display area. Affected leaves are turning yellow and dropping early, and the disease appears to be spreading rapidly between neighbouring plants after a period of wet, windy weather.

   (a)

   Which type of pathogen causes the disease being described here (rose black spot)?

   [1 mark]

   • AFungus
   • BVirus
   • CBacterium
   • DProtist

   (b)

   How is this disease most commonly spread between rose plants?

   [1 mark]

   • ABy direct contact only
   • BBy water or wind
   • CBy a mosquito vector
   • DBy sexual contact

   (c)

   State two ways the disease reduces the growth of an infected rose plant.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A student cuts her finger while cooking. Within moments a small blood clot begins to seal the wound, and over the next few days, if any bacteria did enter through the cut, white blood cells in her blood are ready to respond.

   (a)

   Which of the following is a non-specific defence system that helps prevent pathogens entering the body through the skin?

   [1 mark]

   • AAntibody production
   • BAntitoxin production
   • CThe skin acting as a barrier
   • DPhagocytosis by white blood cells

   (b)

   Which process involves a white blood cell engulfing and digesting a pathogen?

   [1 mark]

   • AAntibody production
   • BAntitoxin production
   • CVaccination
   • DPhagocytosis

   (c)

   Describe two ways, other than phagocytosis, that white blood cells can help defend the body against a pathogen that has entered a wound.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A patient visits her doctor with a sore throat and a high temperature. Tests confirm the infection is caused by a bacterium, and the doctor prescribes a course of antibiotics, as well as a painkiller to help with her symptoms while the antibiotics take effect.

   (a)

   Explain why the doctor prescribed an antibiotic for this infection, and explain why a painkiller alone would not be a suitable treatment on its own.

   [3 marks]

   (b)

   The doctor explains that this antibiotic would not be effective against a viral infection such as a cold. Explain why antibiotics cannot be used to treat viral infections, and why it is difficult to develop drugs that kill viruses without harming the body.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A sexual health clinic reports a rise in cases of gonorrhoea, a bacterial sexually transmitted infection, among young adults in the local area, most of whom did not use barrier contraception. Patients typically present with a thick discharge and pain on urinating, and the infection is being successfully treated with a course of antibiotics, although some strains are becoming increasingly resistant to the antibiotics normally used.

   (a)

   Describe how gonorrhoea is spread, how it is currently controlled and treated, and explain the growing concern about antibiotic resistance mentioned above.

   [6 marks]

   (b)

   Explain how white blood cells respond to this bacterial infection to help destroy the pathogen, and explain, using the general principles of vaccination, why vaccinating people against a disease like measles helps to reduce its spread through a population.

   [6 marks]

   Total for question 4: 12 marks

5. 5
   A commercial tobacco grower notices a distinctive mottled, mosaic-like pattern of yellow and green discolouration developing on the leaves of several plants in one section of the greenhouse. Affected plants show stunted growth, and the pattern spreads to more plants over the following weeks.

   (a)

   Which type of pathogen is responsible for causing this mosaic pattern on the tobacco plant leaves?

   [1 mark]

   • AVirus
   • BFungus
   • CBacterium
   • DProtist

   (b)

   What is the specific name commonly given to this plant pathogen?

   [1 mark]

   • ARose black spot
   • BTobacco mosaic virus
   • CSalmonella
   • DPlasmodium

   (c)

   Explain why the mosaic discolouration on the leaves causes the affected tobacco plants to grow more slowly.

   [2 marks]

   Total for question 5: 4 marks

6. 6
   Each autumn, a large office arranges for staff to receive a flu vaccine, which contains a small quantity of inactive flu virus. Uptake among staff varies: in one year, only 40% of employees were vaccinated and the office experienced a large flu outbreak; the following year, 85% were vaccinated and very few staff became ill.

   (a)

   What does the flu vaccine contain that stimulates the body's immune response?

   [1 mark]

   • AAntibiotics
   • BAntibodies extracted from another person
   • CA small quantity of dead or inactive pathogen
   • DPainkillers

   (b)

   Which type of blood cell produces antibodies in response to the vaccine?

   [1 mark]

   • ARed blood cells
   • BPlatelets
   • CPlasma (the liquid part of blood)
   • DWhite blood cells

   (c)

   Using the information given, explain why far fewer staff became ill with flu in the year when 85% of employees were vaccinated, compared with the year when only 40% were vaccinated.

   [2 marks]

   Total for question 6: 4 marks

7. 7
   A biotechnology laboratory produces monoclonal antibodies to develop a rapid diagnostic test for a specific hormone in urine. Mouse lymphocytes are first stimulated to produce an antibody that binds specifically to this hormone, before being fused with tumour cells to create hybridoma cells that can be grown in culture to produce large quantities of the antibody.

   (a)

   Describe how the hybridoma cells described above are produced, and explain why they are useful for producing large quantities of a specific antibody.

   [3 marks]

   (b)

   Explain why a monoclonal antibody produced in this way is useful for a diagnostic test such as this hormone test, and give one other use of monoclonal antibodies in medicine or research.

   [4 marks]

   Total for question 7: 7 marks

8. 8
   A pharmaceutical company is developing a new antimalarial drug to treat patients infected with the protist that causes malaria, a disease spread between humans by mosquitoes acting as a vector. Before the drug can be prescribed to patients, it must go through a lengthy testing and development process.

   (a)

   Describe the pathogen that causes malaria, how the disease is spread, and one method that could be used to help control its spread.

   [6 marks]

   (b)

   Describe the stages the new antimalarial drug must go through, from initial development to being available for patients, explaining the purpose of each stage.

   [6 marks]

   Total for question 8: 12 marks

End of questions