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93 Cards in this Set
- Front
- Back
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Microbiology
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The study of organisms too small to be seen without magnification
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Microorganisms include:
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Bacteria
Viruses Fungi Protozoa Helminths (worms) Algae |
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Prokaryotes
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(pre-nucleus) Simple cells
unicellular organisms, lack nuclei and membrane-bound organelles |
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Eukaryotes
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(true nucleus) Complex cells
unicellular (microscopic) and multicellular, nucleus and membrane-bound organelles |
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Viruses
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Acellular, composed of a nucleic acid and protein
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Photosynthesis
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Light fueled conversion of carbon dioxide to organic material
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Decomposition
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Breakdown of dead matter and wastes into simple compounds
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Which of the following does NOT describe a fungus?
A. Contains a nucleus B. Has 80S Ribosomes C. Useful in Decomposition D. Is photosynthetic |
D. Is photosynthetic
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Pathogens
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Microbes that do harm
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Spontaneous Generation
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an early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter
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Theory of Biogenesis
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the idea that living things can only arise from other living things
Louis Pasteur eventually disproved spontaneous generation and proved this |
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Antonie van Leeuwenhoek
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Dutch linen merchant
First to observe living microbes Single-lens magnified up to 300X |
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Louis Pasteur
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Showed microbes caused fermentation and spoilage
Disproved spontaneous generation of microorganisms Developed pasteurization |
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Robert Koch
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Established Koch’s postulates - a sequence of experimental steps that verified the germ theory
Identified cause of anthrax, TB, and cholera |
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Taxonomy
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organizing, classifying, and naming living things
-Formal system originated by Carl von Linné |
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Levels of Classification
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Domain - Archaea, Bacteria, & Eukarya
Kingdom Phylum or Division Class Order Family Genus Species |
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Organisms in the same Family must also be in the same Class.
True or False |
True
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Phylogeny
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natural relatedness between groups of organisms
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Three Domains of Life
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Bacteria - true bacteria
Archaea - odd bacteria that live in extreme environments, high salt, heat, etc. Eukarya - have a nucleus and organelles |
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Organisms in the Domain Archaea have more DNA sequence similarity to...
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Eukarya
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All living things (single and multicellular) are made of cells that share some common characteristics:
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-Basic shape – spherical, cubical, cylindrical
-Internal content – cytoplasm, surrounded by a membrane -DNA chromosome(s), ribosomes, metabolic capabilities |
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Characteristics of Life
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-Reproduction and heredity – genome composed of DNA packed in chromosomes; produce offspring sexually or asexually
-Growth and development -Metabolism -Movement and/or irritability : respond to internal/external stimuli; self-propulsion of many organisms -Cell support, protection, and storage mechanisms – cell walls, vacuoles, granules and inclusions -Transport of nutrients and waste |
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Appendages
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-Motility – flagella and axial filaments (periplasmic flagella)
-Attachment or channels –fimbriae and pili |
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Glycocalyx
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surface coating
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Flagella
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-Filament – long, thin, helical structure composed of protein flagellin
-Hook – curved sheath -Basal body – stack of rings firmly anchored in cell wall |
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Monotrichous
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single flagellum at one end
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Lophotrichous
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small bunches emerging from the same site
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Amphitrichous
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flagella at both ends of cell
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Peritrichous
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flagella dispersed over surface of cell
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Signal sets flagella into motion clockwise or counterclockwise:
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Counterclockwise – results in smooth linear direction – run
Clockwise – tumbles |
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Flagellar Response -- Guide bacteria in a direction in response to external stimulus:
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Chemical stimuli – chemotaxis; positive and negative
Light stimuli – phototaxis |
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Internal flagella
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enclosed in the space between the outer sheath and the cell wall peptidoglycan
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Fimbriae
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Fine, proteinaceous, hairlike bristles emerging from the cell surface
Function in adhesion to other cells and surfaces |
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Pili
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-Rigid tubular structure made of pilin protein
-Found only in gram-negative cells -Function to join bacterial cells for partial DNA transfer called conjugation |
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Coating of molecules external to the cell wall, made of sugars and/or proteins:
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Glycocalyx
Two types: Slime layer - loosely organized and attached Capsule - highly organized, tightly attached |
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Functions of the Glycocalyx
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Protect cells from dehydration and nutrient loss
Inhibit killing by white blood cells by phagocytosis, contributing to pathogenicity Attachment - formation of biofilms |
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Gram-positive bacteria
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thick cell wall composed primarily of peptidoglycan and cell membrane
Includes teichoic acid and lipoteichoic acid: function in cell wall maintenance and enlargement during cell division |
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Gram-negative bacteria
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outer cell membrane, thin peptidoglycan layer, and cell membrane
-Inner and outer membranes and periplasmic space between them contains a thin peptidoglycan layer -Outer membrane contains lipopolysaccharides (LPS) |
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retain crystal violet and stain purple
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Gram-positive
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lose crystal violet and stain red from safranin counterstain
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Gram-negative
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mycolic acid
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Lipid cell wall structure of gram positive
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Germination
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return to vegetative growth
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Sporulation
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formation of endospores
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Coccus
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spherical
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Bacillus
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rod
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Spirillum
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helical, comma, twisted rod
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Spirochete
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spring-like
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Coccobacillus
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very short and plump
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Vibrio
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gently curved
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Species
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a collection of bacterial cells which share an overall similar pattern of traits in contrast to other bacteria whose pattern differs significantly
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Strain or variety
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a culture derived from a single parent that differs in structure or metabolism from other cultures of that species (biovars, morphovars)
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Type
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a subspecies that can show differences in antigenic makeup (serotype or serovar), susceptibility to bacterial viruses (phage type) and in pathogenicity (pathotype)
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Nutrition
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process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities
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Essential nutrients
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must be provided to an organism
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Macronutrients
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required in large quantities; play principal roles in cell structure and metabolism (Proteins, carbohydrates)
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Micronutrients or trace elements
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required in small amounts; involved in enzyme function and maintenance of protein structure
(Manganese, zinc, nickel) |
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Organic nutrients
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contain carbon and hydrogen atoms and are usually the products of living things
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Chemotroph
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gain energy from chemical compounds
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Phototrophs
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gain energy through photosynthesis
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Anaerobe
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does not utilize oxygen
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Aerobe
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utilizes oxygen and can detoxify it
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Obligate aerobe
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cannot grow without oxygen
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Facultative anaerobe
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utilizes oxygen but can also grow in its absence
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Microaerophilic
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requires only a small amount of oxygen
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Obligate anaerobe
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lacks the enzymes to detoxify oxygen so cannot survive in an oxygen environment
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Aerotolerant anaerobes
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do not utilize oxygen but can survive and grow in its presence
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Capnophile
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grows best at higher CO2 tensions than normally present in the atmosphere
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Osmotolerant
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do not require high concentration of solute but can tolerate it when it occurs
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Halophiles
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require a high concentration of salt
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Barophiles
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can survive under extreme pressure and will rupture if exposed to normal atmospheric pressure
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Mutualism
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obligatory, dependent; both members benefit
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Commensalism
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commensal member benefits, other member neither harmed nor benefited
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Parasitism
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parasite is dependent and benefits; host is harmed
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Barophiles
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can survive under extreme pressure and will rupture if exposed to normal atmospheric pressure
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Synergism
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members cooperate to produce a result that none of them could do alone
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Mutualism
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obligatory, dependent; both members benefit
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Antagonism
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actions of one organism affect the success or survival of others in the same community
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Commensalism
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commensal member benefits, other member neither harmed nor benefited
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Biofilms
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result when organisms attach to a substrate by some form of extracellular matrix that binds them together in complex organized layers
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Parasitism
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parasite is dependent and benefits; host is harmed
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Quorum sensing
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Communicate and cooperate in the formation and function of biofilms
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Synergism
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members cooperate to produce a result that none of them could do alone
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Division of bacterial cells occurs mainly through ...
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Binary Fission
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Antagonism
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actions of one organism affect the success or survival of others in the same community
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Nƒ = (Ni)2n
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Nƒ is total number of cells in the population
Ni is starting number of cells Exponent n denotes generation time 2n number of cells in that generation |
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Biofilms
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result when organisms attach to a substrate by some form of extracellular matrix that binds them together in complex organized layers
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Quorum sensing
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Communicate and cooperate in the formation and function of biofilms
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Division of bacterial cells occurs mainly through ...
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Binary Fission
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Nƒ = (Ni)2n
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Nƒ is total number of cells in the population
Ni is starting number of cells Exponent n denotes generation time 2n number of cells in that generation |
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Lag phase
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“flat” period of adjustment, enlargement; little growth
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Exponential growth phase
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a period of maximum growth will continue as long as cells have adequate nutrients and a favorable environment
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Stationary phase
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rate of cell growth equals rate of cell death caused by depleted nutrients and O2, excretion of organic acids and pollutants
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Death phase
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as limiting factors intensify, cells die exponentially
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