microorganism
Invisible living thing
A microorganism is a living thing too small to see without magnification—bacteria, viruses, fungi, and single-celled creatures like amoebas.
Some cause disease; others are essential to digestion, decomposition, and fermentation.
The gut contains trillions of microorganisms.
Also spelled micro-organism.
Nucleus-free single-celled organisms
- archaeaThird domain of life
- fungiSpore-reproducing decomposers
- protistsEukaryotic microorganisms, mostly unicellular
- virusMicroscopic infectious agent
protozoa · algae · plankton · prokaryotes · eukaryotes · cyanobacteria · mycoplasma · spirochete
One cell only
- single-celledConsisting of one cell
- invisibleCannot be seen
- minusculeExtremely small in size
- micronMillionth of a meter
nanoscale · multicellular · filamentous · colonial · submicroscopic · ultramicroscopic
Heat-adapted living thing
- anaerobeOrganism needing no oxygen
- aerobeAir-dependent organism
- endosporeBacterial dormancy structure
- astrobiologyStudy of cosmic organisms
Pathogen invasion causing illness
- diseaseDisorder impairing normal function
- contagionDisease spread by contact
- virulenceCapacity to cause disease
- toxinBiological-origin harm agent
germ · outbreak · contamination · transmission · pathogen · epidemic · pandemic · sepsis
Adhesive layer of microorganisms
- colonyDependent territorial settlement
- bloomFlower or flourishing state
- cultureCollective social practices
- populationAll inhabitants combined
community · microbiota · aquatic · marine · freshwater · sediment · phytoplankton · decomposition
Healthful live microorganism supplement
- fermentationMicrobial sugar conversion
- decomposerOrganism breaking down corpses
- nitrogen-fixingConverting N₂ to ammonia
- bioremediationLiving organisms detoxify pollutants
commensal · symbiont · microbiome · yogurt · cheese · brewing · composting · digestion
Gel surrounding the nucleus
- ribosomeProtein synthesis site
- flagellumWhiplike cellular appendage
- capsuleEnclosed dose container
- cell-wallRigid plant cell boundary
plasmid · nucleoid · membrane · chromosome · replication · metabolism · respiration · fermentation
bacteria
Nucleus-free single-celled organisms
- archaeaThird domain of life
- fungiSpore-reproducing decomposers
- protistsEukaryotic microorganisms, mostly unicellular
virus · protozoa · algae · plankton · prokaryotes · eukaryotes · cyanobacteria · mycoplasma · spirochete · amoeba
unicellular
One cell only
- single-celledConsisting of one cell
- invisibleCannot be seen
- minusculeExtremely small in size
micron · nanoscale · multicellular · filamentous · colonial · submicroscopic · ultramicroscopic
thermophile
Heat-adapted living thing
infection
Pathogen invasion causing illness
- diseaseDisorder impairing normal function
- contagionDisease spread by contact
- virulenceCapacity to cause disease
toxin · germ · outbreak · contamination · transmission · pathogen · epidemic · pandemic · sepsis · colonization
biofilm
Adhesive layer of microorganisms
- colonyDependent territorial settlement
- bloomFlower or flourishing state
- cultureCollective social practices
population · community · microbiota · aquatic · marine · freshwater · sediment · phytoplankton · decomposition · symbiosis
probiotic
Healthful live microorganism supplement
- fermentationMicrobial sugar conversion
- decomposerOrganism breaking down corpses
- nitrogen-fixingConverting N₂ to ammonia
bioremediation · commensal · symbiont · microbiome · yogurt · cheese · brewing · composting · digestion · bioprocessing
cytoplasm
Gel surrounding the nucleus
cell-wall · plasmid · nucleoid · membrane · chromosome · replication · metabolism · respiration · fermentation · organelle
microorganismmacroorganism
Organism visible unaided
megafauna · large animal · whale · elephant · giant