Microbiology definitions (Unit 1, Chapter 1)
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88 terms
Terms | Definitions |
|---|---|
 Microbiology | the science that deals with microorganisms and their effects on other forms of life. |
| Medical/Clinical Microbiology | studies pathogens, diseases and body's defenses, epidemiology, transmission, diagnosis, asepsis, treatment, and prevention. |
| Microbes/Microorganisms | Living organisms too small to be seen with the naked eye. |
| Bacteria | Microscopic, single-celled organisms that lack a nucleus; prokaryotes. |
| Parasites | Uni/multicellular organisms that obtain nourishment from it's host. |
| Fungi | Uni/multicellular organisms, heterotrophic eukaryotes that obtain nutrients through absorption. |
| Viruses | Acellular and consist of DNA or RNA (smallest infectious particle) |
| Taxonomy | orderly classification and grouping of organisms into smaller taxa/categories. Based on genotype and phenotype. |
| Genotype | the particular alleles at specified loci present in an organism |
| Phenotype | what an organism looks like as a consequence of its genotype |
| Levels of bacterial classification | Domain Kingdom Division/Phylum Class Order Family Tribe Genus Species Subspecies Serotypes/biotypes |
| Prokaryotes | single-celled organisms that do not have a membrane-bound nucleus. Non-compartmentalized. (bacteria) |
| Eukaryotes | organisms made up of one or more cells that have a nucleus and membrane-bound organelles. Complex organization. (parasites, fungi) |
| Archaeobacteria | literally means ancient bacteria, many are found in extreme environments. Closely related to eukaryotes. Examples include halophilic (salt-loving), thermoacidophilic (heat/acid loving), and methanogenic (methane loving) bacteria. |
| Polar flagella | One flagella at one end of a bacterium, used as a means of locomotion. |
| Peritrichous flagella | Flagella present all round the body of the bacterium used as a means of locomotion. |
| Pili | Appendages that allow bacteria to attach to each other and to transfer DNA during conjugation. |
| Fimbriae | hair-like structures that are shorter, thinner, and straighter than flagella - used to adhere bacterial cells to each other. |
| Mesosome | Plasma membrane that folds into the cytoplasm and increases surface area |
| Gram (+) positive | Have very thick protective peptidoglycan (murein) layer. Retains crystal violet in gram stain. Alternating layers of NAG and NAM. Techoic acid and lipotechoic acid unique to G+ cell wall. Stains blue/purple. |
| Teichoic acid | located on the surface of Gram + bacterial cell walls; covalently bound to peptidoglycan layers; help maintain structure for the peptidoglycan layer |
| Lipoteichoic acid | Teichoic acids covalently linked to lipids that anchor to peptidoglycan of Gram +. |
| N-acetylglucosamine (NAG) | N-acetylglucosamine (NAG), A monosaccharide derivative of glucose that helps form the layered structure of peptidoglycan. |
| N-acetylmuramic acid (NAM) | N-acetlymuramic acid (NAM), The ether of lactic acid and N-acetylglucosamine; this is part of the layered structure peptidoglycan. |
| Gram (-) negative | Bacteria that have less peptidoglycan and are structurally more complex, with an outer membrane that contains proteins, phospholipids, and lipopolysaccharide (LPS). Contains 2 walls: peptidoglycan layer, and LPS. Doesn't retain crystal violet in GS. Stains red/pink. Counterstains are safranin and Carbol fuschin.. |
| Peptidoglycan/murein layer | Bacterial cell wall or murein layer that gives the bacterial cell shape and strength to withstand changes in environmental osmotic pressures (Gram positive have thick peptidoglycan layer with numerous techoic acids; Gram negative have thinner layers.) |
| Lipopolysaccharide (LPS) | Part of the outer membrane; consists of 3 regions: an antigenic O-specific polysaccharide , a core polysaccharide, and an inner lipid A (also called endotoxin). |
| Endotoxin (inner lipid A) | Responsible for producing fever and shock conditions in patients infected with gram- bacteria |
| O-specific polysaccharide | the portion of LPS directed away from the membrane, at the end opposite that of lipid A. |
| Core polysaccharide | LPS; A major component of the outer membrane of gram-negative bacteria, contributing greatly to the structural integrity of the bacteria. |
| Porin proteins | Proteins that form channels for the transport of small molecules across the outer membrane of gram-negative bacterial cell walls. |
| Periplasmic space | The space between the inner and outer cell membranes in Gram-negative bactera. The peptidoglycan cell wall is found in the periplasmic space, and this space sometimes contains enzymes to degrade antibiotics. |
| Acid fast | Used to stain small group of organisms that do not readily take up stain, the cell walls of these bacteria contain high concentrations of lipids, preventing uptake of dyes. Show up faint blue with GS. Very hydrophobic, affects permeability. |
| Mycoplasma | Prokaryote. Lacks a cell wall and can survive without oxygen; can cause pneumonia and urinary tract infection. Lacks rigidity, variety of shapes. |
| Ureaplasma | Prokaryote. Lacks cell wall, similar to mycoplasma; associated with non-gonococcal urethritis and Newborn pneumonia. Lacks rigidity, variety of shapes. |
| Cocci | Spherical-shaped prokaryotes. Further identified in clusters, chains, groups and tetrads. |
| Bacilli | Rod-shaped prokaryotes. Further identified in coccobacilli, bacilli of various sizes (pleomorphic), fusiform bacilli, and palisading. |
| Spirochette | A cork-screw shaped bacterium with axial filaments. Think "spiral." |
| Acridine orange stain | A fluorescent stain used to stain organisms using a fluorescent microscope. At an acid pH, bacteria will stain orange and WBCs will be green. The stain cannot be used to differentiate between gram-positive and gram-negative bacteria. Used in blood cultures. |
| Methylene blue | A stain traditionaly used to stain Corynebacterium diptheriae for observation of metachromatic granules. interacts with nucleic acid molecules and proteins, turning them a dark blue color. |
| Lactophenol cotton blue | The dye that permit to visualization of the fungi under optic microscope. it adheres to the chitin of the fungi walls of hyphae. |
| Calcofluor white | Fluorochrome in chitin of fungi. |
| India ink | Stains background, while white spots appear under microsope as yeast capsules displaces the stain. Cryptococcal meningitis, Cryptococcus neoformans. "halo-like." |
| Autotrophs | organisms that use energy from sunlight or from chemical bonds in inorganic substances to make organic compounds |
| Heterotrophs | organisms that must get energy from food instead of directly from sunlight or inorganic substances |
| Endospore stain | Primary stain: Malachite green, Mordant (what fixes it): Steam; Decolorizer: water; Counterstain: safranin. Spores= green, Cells= pink |
| Endospores | A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions. |
| Nutrient growth media | Contains extracts of meat or soybeans. (nutrient broth, trypticase soy broth) |
| Enriched growth media | Contains added growth factors such as blood, vitamins and yeast extract. (blood agar, chocolate agar) |
| Selective media | Inhibit growth of some bacteria, but allow others to grow. (MacConkey agar [MAC] selective for gram- while inhibiting gram+, and colistin-nalidixic acid [CNA] selective for gram+ while inhibiting gram-) |
| Differential media | Ingredients in media that allow visualization of metabolic differences between groups or species of bacteria. MacConkey agar can be used as this because it distinguishes between lactose fermenters (pink) and nonlactose fermenters (clear). Blood agar can be used in a nonstrict way due to it's hemolytic/nonhemolytic organisms. |
| Transport medium | Used when a delay between collection of the specimen and culture of the specimen. It is a holding medium that preserved viability, but does not allow multiplication. (Stuart broth, Amies, and Cary-Blair) |
| Obligate Aerobes | bacteria that require oxygen to grow |
| Aerotolerant anaerobes | Bacteria that can survive in the presence of oxygen, but do not use oxygen in metabolism. |
| Obligate anaerobes | Bacteria that cannot grow in the presence of oxygen. |
| Facultative anaerobes | Can grow with or without oxygen |
| Capnophilic organisms | Grow best when the atmosphere is enriched with extra carbon dioxide (5-10%). |
| Microaerophilic bacteria | Require a reduced level of oxygen to grow. |
| Psychrophiles | cold loving microbes, grow best between 10-20°C (arctic seas) |
| Mesophiles | moderate temperature loving microbes. Grow best at 20-40°C |
| Thermophiles | Heat loving microbes, grow best at 50-60°C. (hot springs, compost piles) |
| Anticodon | in tRNA, a triplet of nitrogenous bases that is complementary to a specific codon in mRNA |
| Archaea | Single-celled, no nucleus, Live in harsh condisions, oldest organisms on earth |
| Bacteriophage | a virus that is parasitic in bacteria ( it uses the bacterium's machinery and energy to produce more phage until the bacterium is destroyed and phage is released to invade surrounding bacteria) |
| Capsule | An organelle in some prokaryotic cells, such as a bacterial cell located outside the cell wall of bacteria. Usually made of polysaccharides (sticky), but can me made of others. Used by microorganisms as a bodyguard against phagocytosis, and physical and chemical effects of the environment. |
| Codon | three-nucleotide sequence on messenger RNA that codes for a single amino acid |
| Conjugation | the process in which a unicellular organism transfers some of its genetic material to another unicellular organism |
| Dimorphic | occurring or existing in two different forms |
| Eukarya | The domain that includes all eukaryotic organisms. |
| Fermentation | the process by which cells break down molecules to release energy without using oxygen |
| Genus | (biology) taxonomic group containing one or more species |
| Family | (biology) a taxonomic group containing one or more genera |
| Hyphae | the branching, threadlike tubes that make up the bodies of Multicellular fungi |
| Mycelia | filaments in fungi specialized for absorption of nutrients. |
| Lysogeny | the condition of a host bacterium that has incorporated a phage into its own genetic material |
| Phyla | the second largest taxonomic category in the animal kingdom |
| Pathogenic bacteria | Disease causing bacteria |
| Plasmids | small, circular, self-replicating loops of double stranded DNA |
| Pleomorphic | having more than one shape or form |
| Protein expression | forming proteins bases on infromation in DNA and carried out by RNA |
| Respiration | the metabolic processes whereby certain organisms obtain energy from organic moelcules |
| Restriction enzymes | enzyme that cuts DNA at a specific sequence of nucleotides |
| Species | group of similar organisms that can breed and produce fertile offspring |
| Spores | single-celled reproductive bodies highly resistant to cold and heat damage; capable of new organisms |
| Strains | Organisms from the same species that have markedly different traits. |
| Taxa | groups of organisms given names, and may be species, genera, families, orders, classes, phyla, or kingdoms |
| Temperate | not extreme |
| Transduction | Transfer of bacterial genes by a bacteriophage from one cell to another. |
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