The invisible world of bacteria, viruses, and fungi that runs your body and the planet.
12 cards on this page · about a minute each
A working selection from the Mindtrix Microbiology deck, free to read. The app serves a fresh mix from this topic — and everything else you follow — every morning.
Your body contains more microbial cells than your own human cells.
You are not a single organism but a complex biome. Realizing this helps you understand that your health, mood, and cravings are often driven by your internal microbial population, which you can influence through diet.
The ratio of microbial to human cells is roughly 1.3 to 1.
Source: I Contain Multitudes — Ed Yong
Over-sterilizing your environment can weaken your immune system's ability to identify threats.
Your immune system learns by practice. When you live in a perfectly sterile bubble, it can become oversensitive, leading to allergies or autoimmune issues. Exposing yourself to diverse environments helps keep your defenses sharp.
Autoimmune disorders are significantly more common in industrialized nations.
Source: An Epidemic of Absence — Moises Velasquez-Manoff
Your gut bacteria directly influence your brain chemistry and emotional state.
The gut-brain axis is a two-way communication highway. If you feel anxious or depressed for no apparent reason, your microbiome might be signaling a need for different nutrients or fiber.
About 90% of your body's serotonin is produced in your gut.
Source: The Second Brain — Michael Gershon
One course of antibiotics can alter your microbiome for months or years.
Antibiotics are blunt instruments that kill both bad and good bacteria. Avoid them for viral infections like colds; use them only when absolutely necessary to protect your long-term internal health.
Some antibiotics can permanently remove certain microbial species from your gut.
Source: Missing Microbes — Martin J. Blaser
Bacteria use chemical signals to coordinate mass attacks or build biofilms.
This phenomenon, called quorum sensing, shows that bacteria behave like a synchronized collective. Understanding this helps you see that even simple life forms possess complex social strategies and communication.
Bacteria can sense the density of their population to time attacks.
Source: The Social Conquest of Earth — Edward O. Wilson
A significant portion of human DNA originated from ancient viral infections.
Viruses insert their genes into their hosts. Over eons, this has shaped human evolution, providing us with essential genes for things like brain development and immune response.
About 8% of the human genome is ancient viral DNA.
Source: Virolution — Frank Ryan
Fermentation uses microbes to preserve food and unlock hidden nutrients.
By encouraging specific good bacteria to flourish, we prevent harmful microbes from growing. This ancient technique essentially 'pre-digests' food, making vitamins more available to your body.
Fermentation existed before humans understood how it worked.
Source: The Art of Fermentation — Sandor Katz
Your skin hosts a vast array of microbes that defend against invaders.
The bacteria on your skin produce antimicrobial substances that act as a personal chemical barrier. Frequent harsh washing strips this shield, leaving you vulnerable to opportunistic infections.
Your skin has different microbial communities for oily vs dry areas.
Source: The Microbiome Solution — Robynne Chutkan
Bacteria create sticky, protective layers called biofilms that resist antibiotics.
When bacteria form biofilms, they become nearly invincible to cleaning agents. This is why recurring infections, like sinus issues, are so difficult to treat without targeting the biofilm itself.
Dental plaque is a classic example of a biofilm in your mouth.
Source: The Demon Under the Microscope — Thomas Hager
The diversity of microbes in the soil reflects the health of the food grown.
Plants absorb microbes from the soil which become part of your diet. Modern industrial farming kills soil microbes, meaning your produce may look perfect but lack the microbial complexity you need.
A single teaspoon of healthy soil holds more microbes than people on Earth.
Source: The Hidden Half of Nature — David R. Montgomery
Bacteriophages are viruses that target and destroy specific bacteria.
Phage therapy is an ancient, overlooked medical tool that targets only bad bacteria while leaving your good microbes alone. It is a precision weapon that may solve the antibiotic resistance crisis.
Phages are the most abundant biological entities on the planet.
Source: The Perfect Predator — Steffanie Strathdee
Some parasites change the behavior of their hosts to ensure their own survival.
Certain microbes can trigger risk-taking or aggression to spread themselves to new hosts. Recognizing this adds a layer of caution to your health decisions—mind over matter matters.
The parasite Toxoplasma gondii makes mice lose fear of cats.
Source: This Is Your Brain on Parasites — Kathleen McAuliffe
Reading is the easy part. Mindtrix turns these cards into a daily loop: a short deck, a five-question quiz, and a streak that keeps you honest — plus topic mastery and a monthly recap of what you've actually retained.
Start freeMicrobiology: A Very Short Introduction — Nicholas P. Money
