Listed below are the glossary words used in each of the activities. Choose a letter below to skip to that portion of the glossary.
adaptive immune response - portion of the immune system that relies on lymphocytes (B-cells and T-cells) to mount a specific response to a particular pathogen.
aerobes - organisms that grow in the presence of oxygen.
aerobic cellular respiration - cellular respiration that occurs in the presence of oxygen.
agar–seaweed-based hardening agent for culture media.
agglutination - reaction that causes particles (red blood cells as an example) to clump together.
algae–photosynthetic organisms that are members of Domain Eukarya, but are not plants.
allele - a member of a pair of genes controlling a particular trait.
amphipathic - a molecule that contains both hydrophilic and hydrophobic portions.
amphitrichous - having two flagella one at each end of the cell.
anaerobes - organisms that grow in the absence of oxygen.
anaerobic cellular respiration - cellular respiration that occurs in the absence of oxygen.
antibody - a protein present in the serum (liquid portion of blood minus clotting factors) that recognizes and binds with an antigen.
antigen - a substance that interacts with an antibody.
antimicrobial - any chemical or physical agent that destroys microorganisms.
antiseptic - an antimicrobial substance that can be applied to body surfaces.
aseptic - absence of contamination by unwanted microorganisms.
aseptic technique–method to keep out unwanted microorganisms.
asymptomatic carrier - a human that can transmit an infectious disease, but they themselves are not presenting with any signs or symptoms of the disease.
autoclave–machine that generates steam pressure of 15 pounds per square inch; can reach temperatures of 121oC, and will kill even the most resistant forms of microorganisms.
bacillus—a rod-shaped bacterium.
bacteria (bacterium) - unicellular organisms belonging to Domain Bacteria, that lack a nucleus (prokaryotic cells).
bacterial growth - an increase in a bacterial population.
binary fission - the act of splitting into two; a form of asexual reproduction.
biofilm - microbial community that grows on a surface.
broth–liquid medium used to support microbial growth.
budding - a form of asexual reproduction in which a daughter cell develops as a small outgrowth or protrusion of the parent cell.
cellular morphology–-form and structure of an individual cell.
cellular respiration - the breakdown of complex molecules such as carbohydrates into smaller organic molecules, resulting in the release of energy.
cholera - an acute, infectious gastrointestinal disease caused by the bacterium Vibrio cholerae which is usually spread through contaminated drinking water.
chromosome - a rod-shaped or circular mass of DNA that carries hereditary characteristics.
cilia - short, hair-like structures that beat with many others to make a cell move.
Clostridium tetani - A gram-positive, endospore forming, anaerobic bacterium that produces the toxin tetanospasmin (aka tetanus toxin) and causes the disease tetanus.
coccus–-a spherical or ovoid bacterium.
coarse adjustment knob - knob located on the side of the microscope that rapidly brings a specimen into focus.
colony morphology–form and structure of a colony of bacteria or fungi.
colony–visible group of cells that have all formed from the division of one original cell.
colony forming units (CFUs) - aggregates of bacteria (colonies) growing on an agar plate derived from one bacterium.
commensalism - system of interaction in which two organisms live in association with one another; one benefits, and the other neither benefits nor is harmed.
complementary strand - one of two strands making the double helix of DNA.
compound microscope - instrument that makes use of multiple lenses to increase the apparent size of an object.
contaminated materials - material or medium that has been in contact with and is likely to contain infectious microbes.
counterstain—a stain used to give contrast in a differential staining procedure.
coverslip - small piece of thin glass or plastic used on a microscope slide to cover the specimen.
culture media–growth media for the cultivation of microorganisms.
decolorizer–-a solution used in the process of removing a stain.
dermis - thick layer of tissue beneath the epidermis of the skin.
differential staining–-a staining process that distinguishes objects on the basis of reactions to the staining procedure.
diplobacilli–-rods that divide and remain attached in pairs.
diplococci-cocci that divide and remain attached in pairs.
direct counts - counting of bacterial cells or CFUs.
disease - any deviation from the normal state of an organism.
disinfectant -a chemical, often toxic, used on inanimate objects to kill vegetative forms of microorganisms.
disinfection-process of applying disinfectant to the environment to destroy disease-producing microorganisms.
DNA - abbreviation for deoxyribonucleic acid, chemical substance that makes up the genetic material of all cells.
DNA ladder -solution of DNA fragments of known size used to determine the size of an unknown DNA fragment in gel electrophoresis.
ecosystem - level of organization that encompasses all the living components (biotic factors) and non-living components (abiotic factors) of an area.
enumerate - to count or sum.
Enterobacterales - order of gram-negative bacilli, commonly found in the intestinal tract of humans and other animals, that are active fermenters of glucose and other carbohydrates.
epidemic - large number of new cases of a communicable disease occurring for a brief period of time in a specific geographical area. Epidemics sometimes occur in a population in the presence of certain conditions and infectious microbes.
epidermis - the outer layers of the skin, which overlay the dermis.
erythrocyte - red blood cells; carry oxygen around the body.
eukaryotic cells - cells characterized by the presence of a nuclear membrane and membrane-bound organelles.
extrapolymeric substances (EPS) - molecules synthesized by microorganisms and secreted, composed mainly of polysaccharides, proteins and DNA.
facultative anaerobes - organisms that prefer oxygen, but can grow in the absence of oxygen.
fermentation - a special type of cellular respiration that occurs in the absence of oxygen.
flagella - thin, hair-like appendages that propel bacteria and some larger microorganisms.
fine adjustment knob - small knob on the side of the microscope that slowly brings the specimen into fine focus.
gel electrophoresis - technique where an electric current is used to separate molecules of DNA, RNA or protein according to molecular size and charge.
gene - a unit of heredity, made of DNA.
genotype - the genetic makeup of an organism.
genus–"first name" of an organism according to the Linnaean system of classification, and representing organisms with similar characteristics.
Gram stain—a differential stain that divides bacteria into two groups: gram-positive and gram-negative.
gram-negative - a group of bacteria that stain pink or red with the Gram stain. The bacterial walls are composed of a peptidoglycan (carbohydrate and protein) layer surrounded by a lipopolysaccharide (lipid and carbohydrate) outer membrane.
growth rate - the time it takes for a bacterium to undergo one reproductive event.
high dry lens - objective lens that has a magnification between 40X and 50X and is used to view algae, protozoa, and some very large bacteria.
host specificity - the ability of a pathogen to infect only a certain cell/organism.
hydrogen bond - a weak attraction between a hydrogen atom covalently bonded to nitrogen or oxygen and another covalently bonded to nitrogen or oxygen.
hydrophilic - a molecular property showing an attraction to water; “water loving.”
hydrophobic - a molecular property showing a repulsion to water molecules ; “water fearing.”
icosahedral (icosahedron) - three-dimensional object with 20 equilateral triangular faces, 12 vertices and 30 edges.
image - reproduction or likeness of an object.
immersion oil - oil that has approximately the same refractive index (measurement of the deflection from a straight path undergone by a light ray in passing from one medium, such as air, into another) as glass (1.56).
incubator–constant-temperature chamber used to grow microorganisms.
indirect counts - surrogate measures of bacterial growth that do not count cells or CFUs.
infectious disease - disease caused by a microorganism.
innate immune response - portion of the immune system that uses non-specific responses to any type of pathogen.
inoculate - introduce microorganisms into a culture medium or host.
iris diaphragm - shutter-like apparatus below the stage of the microscope that is used to control the amount of light which passes onto a specimen.
lawn - confluent growth of bacteria on an agar surface.
leukocyte - white blood cells; immune cells of the body.
logarithmic serial dilution - the stepwise dilution of a sample based on the power of 10.
lophotrichous - having a tuft or aggregate of flagella at one end of the cell.
low power lens - objective lens that usually has a magnification of 10X and is used to view algae, protozoa, and the arrangement of the specimen.
lysis - the breakdown or destruction of a substance, such as the rupture of the cell membrane.
microbe or microorganism - any of the bacteria, protozoa, viruses, or various fungi and algae.
microorganisms–organisms with single or few cells that can only be viewed using a microscope.
mold – a multicellular fungus that grows as filaments known as hyphae.
monotrichous - having one flagellum at one end of the cell.
morbidity - the condition of suffering from a disease.
mordant - a substance added to a staining solution that makes it stain more intensely
morphology - the external appearance without regard to function.
mortality - death.
motility - the ability of an organisms to move by itself.
mucosal surface - a membrane rich in mucus glands that lines human or animal body passages and cavities that communicate directly or indirectly with the exterior (e.g., mucosa of the respiratory, gastrointestinal, and urogenital systems).
mutation - any change in the sequence of DNA.
mutualism - a relationship between two organisms in which both organisms benefit.
non-polar - a property of a covalent bond where the electrons are shared equally (or the symmetry of the molecule offsets the charge) and thus there are no dipoles created.
notifiable diseases - diseases that are required by law to be reported to health officials.
nucleotide - a class of compounds consisting of a carbohydrate (sugar), a purine or pyrimidine base, and a phosphate group.
objective lenses - lenses attached to the nosepiece of the microscope; the second in the series of lenses in a compound microscope.
obligate aerobe - organism that can grow only in the presence of oxygen.
obligate anaerobe - organism that can grow only in the absence of oxygen.
ocular lens - lens closest to the eye that usually has a magnification of 10X; the first in the series of lenses in a compound microscope.
oil immersion lens - most powerful of the objective lenses and, with oil, is used to view bacteria; usually has a magnification of l00X.
opportunistic pathogen - an organism that does not ordinarily cause a disease but can become pathogen (i.e., cause disease) under certain circumstances.
optimum temperature - the temperature at which a given species grows the best.
osmotic pressure - the force exerted by substances dissolved in a solution on a membrane they cannot penetrate.
parasitism - a relationship between two organisms in which one benefits (parasite) at the expense of another (host).
pathogen - disease-causing microbe.
peritrichous - having flagella distributed over the entire cell.
petri dish–plastic container used to grow microorganisms.
pH - a representation of the alkalinity (low concentration of H+) or acidity (high concentration of H+) of a substance.
phagocytosis - process by which cells ingest solid material.
phenotype - the physical, observable traits of an organism.
phototrophs - organisms that use light as their energy source.
pigments - molecules that absorb light.
planktonic bacteria - free-living bacteria.
polar - a property of a covalent bond where the electrons are not shared equally and a portion of the molecule is positively charged, while another area is negatively charged.
precipitate - the formation of a solid substance from an aqueous solution.
primary dye–-the first dye used in a differential staining procedure.
probe - a single stranded DNA or RNA sequence that searches and binds to its complementary sequence.
probiotics - foods or supplements that contain living bacteria.
prokaryotic cells - cells characterized by a lack of a nuclear membrane and membrane-bound organelles.
protozoa- a wide range of microorganisms that are members of Domain Eukarya that feed on organic material.
pseudopod - foot-like projections of the cell’s cytoplasm used to feed and move the cell.
pure culture–culture of microorganisms that contains only one genus and one species.
restriction enzyme - a bacterial protein that cuts DNA at specific sequences known as restriction sites.
ribosome - cytoplasmic particle where proteins are made in the cell, consists of ribosomal RNA (rRNA) and protein.
RNA - abbreviation for ribonucleic acid, chemical substance that is involved in protein synthesis; three types of RNA found in the cell are messenger RNA (mRNA, carries the message for what protein is to be made), transfer RNA (tRNA, delivers amino acids to the ribosome) and ribosomal RNA (rRNA, makes up the ribosome).
semi-solid agar - partially solid culture medium made by the addition of a lower percentage of agar than is used for the totally solid agar. It allows for the movement of motile organisms within the agar itself.
septation - a cross wall between cells.
serial dilution - a standard scientific method in which a substance is stepwise diluted based on a constant.
sewage contamination - direct contact of sewage with water supply.
slant–culture medium containing agar that is allowed to harden at an angle.
soap - substance used as a cleaning agent, made of salts of fatty acids.
source of contamination - original reservoir of infectious organisms that may lead to acquisition of infection by an exposed person.
species–a closely related population of microorganisms; also the "second name" of an organism according to the Linnaean system of classification.
spirillum–-a helical or corkscrew-shaped bacterium; when capitalized to refer to a genus, it refers to aerobic, helical bacteria with clumps or polar flagella.
stab culture - Bacteria are inoculated into an agar tube with a pipet tip or needle.
stage-flat area of the microscope that holds the microscope slide.
staphylococci–-a grape-like cluster or broad sheet of spherical cocci.
sterile–free of living organisms.
sterile technique–see aseptic technique
streptobacilli–-rods that remain attached in chains after cell division.
streptococci–-a family of gram-positive cocci whose cells occur as pairs or chains, exhibit ing facultatively anaerobic fermentative metabolism.
swarming - the phenomenon exhibited by certain actively motile organisms in which they are able to rapidly spread over the surface of a moist agar plate. A feature of this activity is its periodicity: it occurs in successive waves, separated by periods of growth and cell division.
swimmer - the term used to describe a motile cell with extra flagella.
Typticase Soy Agar - a soybean casein digest solid medium that supports the growth of various bacteria.
turbid - having a cloudy appearance.
turbidity - measure of the opaqueness of a liquid.
ubiquitous-widespread.
ultraviolet light - atoms that travel at a wavelength of 13.46 to 400 nanometers; radiation of these wavelengths are most harmful to microorganisms.
vehicle - carrier of infectious organisms to humans.
viability - ability to be alive.
virus–submicroscopic, parasitic, filterable agent consisting of a nucleic acid surrounded by a protein coat and replicates only inside a living cell.
wet mount-placement of a drop of a liquid containing microorganisms on a microscope slide; a coverslip is placed on top of the drop to protect the microscope lenses from damage.
Winogradsky column - a miniature ecosystem that can be utilized to enrich for phototrophic bacteria.
yeast–unicellular fungus belonging to the class Ascomycetes (sac fungi).