2.6 Microorganisms

• Types of microorganisms: fungi, bacteria and viruses
• Modes of transmission of microorganisms
• Infections caused by microorganisms in human beings
• Prevention and control of infections
• Economic importance of microorganisms

• identify microorganisms that affect human beings
• explain modes of transmission of microorganisms in human beings
• identify types of infections caused by microorganisms in human beings
• describe methods of control and prevention of infections caused by microorganisms
• explain the economic importance of microorganisms
• appreciate the effect of microorganisms in day-to-day life

“Why do antibiotics cure a throat infection but do nothing for a cold?”

“How does washing hands with soap actually stop disease?”

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1. Microorganisms and how they spread
   40 min · 2 practice tasks · quiz
   Three very different kinds of organism, the diseases they cause, and the routes they travel.
2. Preventing infection, and the microorganisms we need
   40 min · 2 practice tasks · quiz
   How to break the chain of infection, and why life would be impossible without microorganisms.
3. Bacteria: cells that divide in two
   40 min · 1 practice tasks · quiz
   A bacterium is one cell with no true nucleus. Binary fission, Kenyan diseases, and why antibiotics can work.
4. Fungi: threads, yeasts and spores
   40 min · 1 practice tasks · quiz
   Fungal cells have a true nucleus. They grow as hyphae or as yeasts, spread by spores, and need antifungals not antibiotics.
5. Viruses: not a cell
   40 min · 1 practice tasks · quiz
   A virus is genetic material in a protein coat. It only reproduces inside a host cell, which is why antibiotics fail.
6. Observing microorganisms safely
   40 min · 1 practice tasks · quiz
   What a school microscope can show, what it cannot, and the rules that keep a culture from becoming an outbreak.
7. Spread by air: droplets and coughing
   40 min · 1 practice tasks · quiz
   Coughs, sneezes and talk throw droplets. TB, measles, influenza and COVID-19 ride that route, so ventilation and covering coughs matter.
8. Spread by water and food
   40 min · 1 practice tasks · quiz
   Cholera, typhoid and food poisoning follow the faecal-oral route. Boil, cook, cover, and keep latrines away from wells.
9. Vectors, wounds and body fluids
   40 min · 1 practice tasks · quiz
   Some organisms hitch a ride on an insect or enter through a cut, sex, a needle or from mother to child.
10. Infections that matter in Kenya
    40 min · 1 practice tasks · quiz
    TB, HIV, measles, cholera and malaria sit on different routes. Naming the organism and the route is how you choose the control.
11. Vaccination: a safe first meeting
    40 min · 1 practice tasks · quiz
    A vaccine prepares memory cells so the real infection is not your first. KEPI exists because of that biology.
12. Hygiene and community control
    40 min · 1 practice tasks · quiz
    Soap, sanitation, isolation and completing treatment are chain-breakers. Design a control that fits the community you actually live in.
13. Useful microorganisms in food and medicine
    40 min · 1 practice tasks · quiz
    Yeast, lactic acid bacteria and moulds make food and drugs. The same biology as disease, pointed at a job we want.
14. Useful microorganisms in soil and waste
    40 min · 1 practice tasks · quiz
    Decomposers, nitrogen-fixing bacteria, biogas and sewage treatment: the organisms that keep land and people alive.