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Biology · Microbiology

Microbe Zoo

Zoom from your hand down to a virus, watch bacteria double on a plate, build a virus shell, and run an outbreak with a slider for R₀ and vaccination.

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The course

7 worlds · 31 lessons

World 1 · How Small Is a Germ?

FREEFrom your hand down to a virus
  1. 01Powers of ten: from your hand to a germEach step is ten times smaller · 11 min
  2. 02Millimetres, micrometres, nanometresThe units of the invisible · 10 min
  3. 03Seeing the invisibleWhy a light microscope cannot see a virus · 12 min
  4. 04Meet the microbe familyBacteria, archaea, fungi, protists and viruses · 12 min

World 2 · Bacteria: Friends and Foes

PROA whole cell with no nucleus
  1. 01Anatomy of a bacteriumA whole cell with no nucleus · 12 minPRO
  2. 02Shapes and the Gram stainSorting bacteria by what you can see · 12 minPRO
  3. 03Bacteria that work for usGut, yoghurt, fish tanks and insulin · 13 minPRO
  4. 04How a few bacteria cause illnessPathogens, toxins and germ theory · 13 minPRO

World 3 · Doubling on a Plate

PROHow one cell becomes a billion
  1. 01Binary fission: one becomes twoHow bacteria reproduce · 11 minPRO
  2. 02The doubling rule: N = N₀ × 2^(t/td)Why one cell can become a billion · 14 minPRO
  3. 03The four phases of a growth curveLag, log, stationary, death · 12 minPRO
  4. 04Counting colonies: serial dilutionHow to count what you cannot see · 14 minPRO
  5. 05Warm food, cold foodTemperature steers doubling time · 12 minPRO

World 4 · Build a Virus

PROGenes in a coat
  1. 01A virus is not a cellGenes in a coat · 11 minPRO
  2. 02Capsid geometry: why icosahedra?20 faces, 12 corners, 60 copies · 14 minPRO
  3. 03Hijack: the lytic cycleHow a virus makes copies of itself · 12 minPRO
  4. 04Lytic or lysogenic? The patient strategyViruses that wait · 12 minPRO
  5. 05Why viruses keep changingCopying errors and shuffled genomes · 13 minPRO

World 5 · Why Soap Works

PROMolecules, envelopes and clean hands
  1. 01The soap moleculeA head that loves water, a tail that hates it · 12 minPRO
  2. 02Soap against viruses and bacteriaBreaking envelopes and washing things off · 13 minPRO
  3. 03Washing hands properlyTwenty seconds and every corner · 12 minPRO
  4. 04Heat, alcohol and sterilisationCleaning, disinfecting, sterilising · 14 minPRO

World 6 · Antibiotics and Resistance

PROMedicines, evolution and sharing genes
  1. 01What antibiotics are, and what they are notAnd how they find their targets · 13 minPRO
  2. 02Evolution on a plateSelection in a few generations · 14 minPRO
  3. 03Sharing resistancePlasmids, conjugation and friends · 12 minPRO
  4. 04Slowing resistanceEveryone has a part · 12 minPRO

World 7 · Vaccines, Outbreaks and Herd Immunity

PROTraining the body and modelling the crowd
  1. 01How vaccines train the bodyA safe preview of the enemy · 13 minPRO
  2. 02Kinds of vaccineAnd how we know they are safe · 14 minPRO
  3. 03The outbreak modelSusceptible, Infected, Recovered · 14 minPRO
  4. 04R₀ and the reproduction numberOne case, how many more? · 13 minPRO
  5. 05Herd immunityProtecting the people who cannot be vaccinated · 14 minPRO