Checklist Questions

• Types of pathogen


  • Bacteria
  • Virus
  • Fungi
  • Protists
• Diseases caused by pathogens

  • Tuberculosis (bacteria)
  • Influenza (virus)
  • Candidiasis (candida albicans) (fungi)
  • Malaria (plasmodium) (protists)
• Mechanical barriers that prevent pathogens from entering the body

  • Nose-nasal hair keeps out dust + larger microorganisms. Mucus production also helps trap pathogens
  • Skin-complete barrier against pathogens (unless cut) and produces antimicrobial secretions
  • Trachea and Bronchi-Produces mucus to catch pathogens and are lined with cilia (hairs)
• Chemical barriers that prevent pathogens from entering the body

  • Saliva-antibacterial enzymes
  • Tears-antibacterial enzymes
  • Stomach acid-low pH and produces hydrochloric acid to kill harmful microbes
  • "Good" gut bacteria-the good gut bacteria out competes the bad
• Phagocytosis


  1. Recognize antibodies on surface of foreign pathogen

  2. Extends cell membrane around particle forming a phagosome

  3. Phagosome encloses it in phagocytes cytoplasm

  4. Phagosome merges with lysosomes forming phagolysosome

  5. Lysosomes break down engulfed particle into smaller molecules + digest it
• Antibody Production


  1. Pathogen invades body. Pathogen has antigen on surface

  2. White blood cells detect antigen as foreign

  3. B-Lymphocytes produce specific antibodies for foreign antigens

  4. Antibodies lock onto antigens +destroy invading cell

  5. Many more antibodies produced +carried around body to kill similar cells

  6. Memory white blood cells produced + remain in body incase of secondary infection
• Epidemic


  Sudden increase in number of cases of a disease within specific community beyond what's normally expected. Disease outbreak limited to certain area or population
• Pandemic


  An epidemic that spreads across multiple countries/continents affecting large number of people. Global outbreak of disease + spreads easily
• Endemic


  Consistently present in particular geographic area/population. Disease that is always there at more or less constant level within specific region or group of people
• Global warming


  May lead to an increase in the frequency of new pandemics
• How a vaccine prepares the body against infection

  1. An inactive pathogen is injected into the body

  2. White blood cells recognise the pathogen as a foreign body and create antibodies for it

  3. The antibodies lock onto the antigen and destroy it

  4. White blood cells then create memory cells incase of an actual infection which the body will think is the second one

  5. If the body gets infected with the actual disease the memory cells will recognise it and antibodies will be mass produced very quickly and destroy the pathogen before it makes the person sick
• Edward Jenner produced the first vaccine
• Benefits of vaccination programmes

  • Reduced amount of infectious disease diagnoses
  • Protects vulnerable populations (e.g pregnant women, old people)
  • Herd immunity ( large part of population vaccinated = indirect protection to unvaccinated by reducing spread of disease)
• Risks of vaccination programmes

  • Adverse reactions (e.g fever, allergic reactions)
  • Might not work on weak immune system
  • Rare side effects
• Antibiotics


  Medications that fight bacterial infections by killing them or stopping growth
• How antibiotics work


  • Specifically target bacterial cells while leaving human cells unharmed
  • Interfere with processes that are needed for bacterial survival (different to humans)
  • Preventing bacteria from making cell wall (needed for support + protection)
• Some antibiotics affect many different bacteria in body + good gut bacteria
• Some antibiotics affect less and they are better to use
• Most antibiotics have no effect on immune system
• How antibiotic resistance arises in bacteria

  1. When you take dose of antibiotics, some bacteria in population unaffected by treatment because of (resistant) genes, antibiotics can't kill them

  2. If you don't complete your antibiotics cycle, they can reproduce and pass their resistance onto their offspring

  3. Whole new populations which are unaffected by antibiotics can't be treated by them