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Viruses, Fungi and Protozoa

Edexcel A-level BiologyTopic 4 of 1617 lessons

Revision notes for Viruses, Fungi and Protozoa in Edexcel Biology (9BI0). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.

  1. Viral DiseasesA virus is a non-living, acellular particle that can only reproduce inside a living host cell, so all viruses are obligate intracellular parasites.
  2. InfluenzaInfluenza (flu) is caused by the influenza virus, an enveloped RNA virus.
  3. Transmission of InfluenzaInfluenza spreads from person to person mainly through the air.
  4. Pathogenic Effects of InfluenzaOnce influenza viruses enter the airways, they infect and destroy the ciliated epithelial cells lining the nose, trachea and bronchi.
  5. Treatment and Control of InfluenzaAntibiotics do not work against influenza, because viruses have no cell walls, ribosomes or metabolism for antibiotics to target.
  6. Fungi as PathogensFungi are eukaryotic organisms with cell walls made of chitin.
  7. Puccinia graminisPuccinia graminis is the fungus that causes stem rust (black rust) of wheat.
  8. Transmission of Stem RustStem rust spreads between wheat plants by wind-borne spores.
  9. Pathogenic Effects of Stem RustStem rust damages wheat in several ways, and a severe infection a few weeks before harvest can destroy an entire crop.
  10. Treatment and Control of Stem RustStem rust cannot be cured once a plant is badly infected, so farmers focus on preventing infection and slowing its spread.
  11. Protozoa as PathogensProtozoa are single-celled eukaryotic organisms in the kingdom Protoctista.
  12. Plasmodium spp.Malaria is caused by protozoa of the genus Plasmodium ('spp.' means several species).
  13. Transmission of MalariaMalaria is not passed directly from person to person.
  14. Pathogenic Effects of MalariaThe symptoms of malaria are caused mainly by the blood stage, when merozoites multiply in red blood cells.
  15. Endemic DiseasesA disease is endemic when it is always present in a particular population or region, at a fairly constant, expected level.
  16. Treatment, Prevention and Control of MalariaTreatment.
  17. Preventing the Breeding of MosquitoesFemale Anopheles mosquitoes lay their eggs on the surface of still or slow-moving water.

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