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Flashcards · Biology

Defence Against Disease

65 cards from 4 lessons

  1. What are the body's non-specific defences?

    Barriers such as the skin, nose, trachea and bronchi, and stomach that work against all pathogens.

  2. How does the skin protect the body?

    It is a barrier that most pathogens cannot pass, and platelets seal any cuts with a scab.

  3. How does the nose protect the body?

    Hairs and mucus trap pathogens in the air.

  4. How do the trachea and bronchi protect the body?

    Mucus traps pathogens and cilia move it up to be swallowed.

  5. How does the stomach protect the body?

    It makes hydrochloric acid, which kills pathogens.

  6. What is the immune system?

    White blood cells that try to destroy pathogens that get into the body.

  7. What is phagocytosis?

    A white blood cell engulfing and digesting a pathogen.

  8. What is an antigen?

    A molecule on the surface of a pathogen.

  9. What is an antibody?

    A protein made by white blood cells that sticks to a specific antigen.

  10. Why is each antibody specific?

    Its shape fits the antigen of only one type of pathogen.

  11. What do antitoxins do?

    They neutralise the toxins made by bacteria.

  12. Which cells make antibodies?

    Lymphocytes (white blood cells).

  13. What happens to a pathogen covered in antibodies?

    It is destroyed, often by phagocytes.

  14. What do cilia do in the airways?

    Move mucus, with trapped pathogens, up towards the throat.

  15. Which defence is non-specific, phagocytosis or antibodies?

    Phagocytosis.

  16. A body with a pointer marked X to the stomach. Name the defence marked X and say how it protects the body.

    The stomach. It produces hydrochloric acid, which kills most of the pathogens that are swallowed.

  17. A body outline with no labels. Label the body's non-specific defences. The same body with each defence labelled.

    Skin (tough barrier), nose (hairs and mucus), trachea and bronchi (mucus and cilia) and stomach (hydrochloric acid).

  18. What is vaccination?

    Introducing small quantities of dead or inactive forms of a pathogen into the body.

  19. What does a vaccine stimulate?

    The white blood cells to produce antibodies.

  20. Why does a vaccine not make you ill?

    The pathogens in it are dead or inactive.

  21. What happens if the real pathogen later enters a vaccinated person?

    The white blood cells respond quickly and make the correct antibodies.

  22. Why is the second response faster?

    Memory cells remember the antigen.

  23. What is herd immunity?

    When most people are immune, so the disease cannot spread easily and protects the unvaccinated.

  24. Who benefits from herd immunity?

    People who cannot be vaccinated, such as babies or the very ill.

  25. Name a disease that has been eradicated by vaccination.

    Smallpox.

  26. What happens if fewer people are vaccinated?

    The disease can spread again.

  27. Why do some pathogens need new vaccines regularly?

    Their antigens change, as in flu viruses.

  28. What is a vaccination schedule?

    A plan of when each vaccine is given. You do not need to know it.

  29. Give one benefit of vaccination to a country.

    It saves lives and money spent on treatment.

  30. Give one concern about vaccination.

    A small number of people react badly, which can put others off.

  31. Does vaccination work on bacteria and viruses?

    Yes, there are vaccines against both.

  32. What are memory cells?

    White blood cells that remain after an infection or vaccination.

  33. Four numbered panels showing vaccination with no labels. Describe what is happening at each step. The four steps of vaccination with their headings.

    1 Vaccine given: dead or inactive pathogens. 2 Antibodies and memory cells are made. 3 The real pathogen arrives later. 4 A fast response destroys it, so there is no illness.

  34. What do antibiotics do?

    They kill bacteria inside the body, curing bacterial disease.

  35. Give an example of an antibiotic.

    Penicillin.

  36. Why must the right antibiotic be used for a bacterial disease?

    Antibiotics are specific. Each works on certain bacteria only.

  37. Do antibiotics kill viruses?

    No.

  38. Why do antibiotics not kill viruses?

    Viruses live and reproduce inside cells, and do not have the structures that antibiotics attack.

  39. Why is it difficult to make drugs that kill viruses?

    They would also damage the body's own cells.

  40. What do painkillers do?

    They reduce the pain and other symptoms of a disease.

  41. Do painkillers kill pathogens?

    No.

  42. What is antibiotic resistance?

    When bacteria are no longer killed by an antibiotic.

  43. How does a resistant strain arise?

    A mutation makes a bacterium resistant, it survives the antibiotic, and it reproduces.

  44. Why is antibiotic resistance a concern?

    Infections become harder to treat, and people may die from infections that were once easily cured.

  45. How can resistance be reduced?

    Do not overuse antibiotics, and finish the course.

  46. What is MRSA?

    A strain of bacteria that is resistant to many antibiotics.

  47. Why shouldn't you take antibiotics for a cold?

    A cold is caused by a virus, so antibiotics do not work.

  48. What has happened to deaths from bacterial diseases since antibiotics?

    They have greatly decreased.

  49. Four numbered panels about antibiotic resistance with no labels. Describe what is happening at each step. The four steps of antibiotic resistance with their headings.

    1 A population with one resistant bacterium. 2 The antibiotic kills the non-resistant bacteria. 3 The resistant bacterium survives and divides. 4 A resistant strain: the antibiotic no longer works.

  50. Name a drug that comes from foxgloves.

    Digitalis, a heart drug.

  51. Which painkiller originates from willow?

    Aspirin.

  52. Who discovered penicillin?

    Alexander Fleming.

  53. Which mould makes penicillin?

    Penicillium.

  54. How are most new drugs made today?

    They are synthesised by chemists in the pharmaceutical industry.

  55. What three things are new drugs tested for?

    Toxicity, efficacy and dose.

  56. What is toxicity?

    How harmful the drug is.

  57. What is efficacy?

    Whether the drug works.

  58. What is preclinical testing?

    Testing in the laboratory using cells, tissues and live animals.

  59. Who is in the first stage of a clinical trial?

    Healthy volunteers, at a very low dose.

  60. Why do later trials use patients?

    To find the best dose and to check that the drug works.

  61. What is a placebo?

    A dummy treatment with no drug in it.

  62. What is a double-blind trial?

    A trial where neither the patients nor the doctors know who has the real drug.

  63. Why use a double-blind trial?

    To stop patients' or doctors' expectations affecting the results.

  64. What is peer review?

    Other scientists checking the results before they are published.

  65. A five-stage pipeline with no labels. Describe each stage in developing a new drug. The same pipeline with each stage labelled.

    1 Discovery. 2 Preclinical testing on cells, tissues and animals. 3 Safety trial with healthy volunteers at a very low dose. 4 Patient trials to find the best dose and check it works. 5 Peer review and use.