Microbiology Terms
Microbiology studies microscopic life: bacteria, archaea, viruses, fungi and protozoa. These terms cover how microbes are built, grow and are identified in the lab, how they cause disease, how antibiotics work, and why resistance to them spreads.
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A
- AgarMicrobiologyAgar is a jelly-forming polysaccharide extracted from red seaweeds, used above all to solidify culture media for growing microorganisms.
- AntibioticMicrobiologyAn antibiotic is a drug that kills bacteria or stops them from growing, used to treat or prevent bacterial infections; it has no effect on viruses.
- Antibiotic resistanceMicrobiologyAntibiotic resistance is the ability of bacteria to survive and multiply despite an antibiotic that once killed them or stopped their growth.
- AntigenImmunologyAn antigen is any molecule the immune system can recognize as a target, especially one that prompts antibodies or T cells to respond against it.
- ArchaeaMicrobiologyArchaea are single-celled prokaryotes that form their own domain of life, distinct from bacteria in their membranes, cell walls and genes.
- Aseptic techniqueMicrobiologyAseptic technique is the set of practices that keeps microbes from contaminating sterile materials, cultures or a patient's tissues during a procedure.
B
- Bacterial conjugationMicrobiologyBacterial conjugation is the direct transfer of DNA, usually a plasmid, from one bacterial cell to another through a pilus and close cell contact.
- Bacterial growth curveMicrobiologyA bacterial growth curve is a graph of living cell numbers over time in a closed culture, showing lag, exponential, stationary and death phases.
- Bacterial transformationMicrobiologyBacterial transformation is the uptake of free DNA from the surroundings by a bacterial cell, which can then gain the genes that DNA carries.
- BacteriophageVirologyA bacteriophage, or phage, is a virus that infects bacteria, injecting its genome and using the host cell's machinery to make new phages.
- BacteriumMicrobiologyA bacterium is a single-celled prokaryote with no nucleus, found in almost every habitat on Earth, including in and on the human body.
- Binary fissionMicrobiologyBinary fission is how bacteria and archaea reproduce: a cell copies its DNA, grows, and splits in the middle into two identical daughter cells.
- BiofilmMicrobiologyA biofilm is a community of microbes stuck to a surface and to each other inside a slimy matrix they produce, such as the plaque on teeth.
- BioremediationBiotechnologyBioremediation is the use of living organisms, mostly microbes and sometimes plants, to break down or remove pollutants from soil, water or air.
C
- Cell wallCell BiologyA cell wall is a rigid layer outside the plasma membrane of plant, fungal, algal and most bacterial cells that gives shape and stops them bursting.
- Communicable diseasePublic HealthA communicable disease is an infection that can pass from one person or animal to another, directly or through air, water, food, objects or vectors.
D
E
- EndosporeMicrobiologyAn endospore is a tough, dormant structure formed inside some bacteria, such as Bacillus and Clostridium, that survives heat, drying and chemicals.
- Escherichia coliMicrobiologyEscherichia coli is a rod-shaped, gram-negative gut bacterium that is mostly harmless but includes strains that cause diarrhea and urinary infections.
F
- FermentationBiochemistryFermentation is a way cells get energy from sugar without oxygen, passing electrons to an organic molecule so that glycolysis can keep going.
- FlagellumMicrobiologyA flagellum is a long, whip-like projection that some cells, including many bacteria and sperm, use to swim through liquid.
- FungusMycologyA fungus is a eukaryote, such as a yeast, mold or mushroom, that has chitin in its cell walls and feeds by absorbing nutrients from its surroundings.
G
- GiardiaParasitologyGiardia is a genus of flagellated protozoan parasites; Giardia duodenalis infects the small intestine and causes giardiasis, a common diarrheal illness.
- Gram stainMicrobiologyThe Gram stain is a lab staining method that sorts bacteria into Gram-positive (purple) and Gram-negative (pink) groups based on their cell walls.
- Gram-negative bacteriaMicrobiologyGram-negative bacteria have a thin peptidoglycan wall wrapped in an outer membrane, so they lose the purple dye in a Gram stain and look pink.
- Gram-positive bacteriaMicrobiologyGram-positive bacteria have a thick peptidoglycan cell wall and no outer membrane, so they keep the purple crystal violet dye in a Gram stain.
H
I
L
- Lysogenic cycleVirologyThe lysogenic cycle is a phage life cycle in which viral DNA joins the host bacterium's chromosome and is copied with it instead of killing the cell.
- Lytic cycleVirologyThe lytic cycle is a viral life cycle in which a phage takes over a bacterial cell, makes many copies of itself, then bursts the cell to release them.
M
- MetagenomicsGenomicsMetagenomics is the study of all the DNA recovered directly from a sample, such as soil, seawater or stool, to reveal its whole community of microbes.
- MicrobiomeMicrobiologyA microbiome is the community of bacteria, fungi, viruses and other microbes, with their genes, that lives in a particular place, such as the human gut.
- MoldMycologyA mold is a fungus that grows as a fuzzy network of branching threads called hyphae, often seen on damp walls and spoiling food.
- MRSAMicrobiologyMRSA is any strain of the bacterium Staphylococcus aureus that resists methicillin and nearly all other beta-lactam antibiotics, including penicillins.
- MycosisMycologyA mycosis is a disease caused by fungi infecting the body, from mild skin infections like athlete's foot to life-threatening lung or blood infections.
N
O
P
- PathogenMicrobiologyA pathogen is a microbe or other agent, such as a virus, bacterium, fungus, parasite or prion, that can cause disease in a host.
- PenicillinPharmacologyPenicillin is a group of beta-lactam antibiotics, first found in a mold, that kill bacteria by blocking the building of their cell walls.
- PeptidoglycanMicrobiologyPeptidoglycan is the mesh-like polymer of sugars and short peptides that forms the bacterial cell wall and gives bacteria their shape and strength.
- PlasmidMolecular BiologyA plasmid is a small, usually circular DNA molecule that copies itself independently of the main chromosome, found mostly in bacteria.
- PlasmodiumParasitologyPlasmodium is a genus of single-celled parasites, spread by Anopheles mosquitoes, that infect liver and red blood cells and cause malaria.
- PneumoniaMedicinePneumonia is an infection of one or both lungs in which the tiny air sacs fill with fluid and pus, making it harder to take in oxygen.
- ProbioticMicrobiologyA probiotic is a live microbe, usually a bacterium or yeast, taken in large enough numbers to give a health benefit shown in studies.
- ProkaryoteCell BiologyA prokaryote is a usually single-celled organism, a bacterium or an archaeon, whose cell has no nucleus or other membrane-bound organelles.
- ProtozoaParasitologyProtozoa are single-celled eukaryotes that do not photosynthesize, usually move on their own and feed on other organisms or organic matter.
- PutrefactionForensic MedicinePutrefaction is the breakdown of a dead body's soft tissues by bacteria, which produces gas, discoloration and the foul smell of decay.
Q
R
S
- SepsisPathologySepsis is a life-threatening emergency in which the body's reaction to infection runs out of control and damages its own tissues and organs.
- SporeMycologyA spore is a small, hardy reproductive cell made by fungi, plants and some microbes that can spread widely and grow into a new organism on its own.
- Staphylococcus aureusMicrobiologyStaphylococcus aureus is a gram-positive bacterium, carried in the nose by about a third of people, that causes skin and invasive infections.
- SterilizationMicrobiologyIn microbiology, sterilization is any process that kills or removes all microbial life, including bacterial endospores and viruses, from an object.
- SymbiosisEcologySymbiosis is a close, long-lasting relationship between two different species that may benefit both, benefit one, or benefit one at the other's expense.
T
- TransductionMicrobiologyIn microbiology, transduction is the transfer of bacterial DNA from one cell to another by a bacteriophage, a virus that infects bacteria.
- TuberculosisMedicineTuberculosis is a contagious disease caused by the bacterium Mycobacterium tuberculosis that most often attacks the lungs and spreads through the air.
U
V
- Viral envelopeVirologyA viral envelope is the outer lipid membrane, taken from a host cell and studded with viral proteins, that surrounds the capsid of some viruses.
- VirusVirologyA virus is a tiny infectious particle of DNA or RNA inside a protein coat that can multiply only by taking over the machinery of a living host cell.
Y
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