Microbiology Test 1 Test Questions – Flashcards
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Unlock answers| microbiology |
| study of microscopic forms of life |
| pathogen |
| disease causing microorganisms |
| nonpathogen |
| microbes that do not cause disease |
| opportunistic pathogen |
| microbes that do not cause disease under ordinary conditions, but have the potential to cause disease should the opportunity present itself |
| acellular microbes |
| microbe not composed of cells aka: infectious particles Ex: prions and viruses |
| cellular microbes |
| microbe composed of cells Ex: procaryotes- archaea, bacteria eucaryotes- algae, fungi, protozoa |
| Reasons why microbes are important: |
-produce oxygen -involved in decomposition of dead organisms and the waste products of living organisms -decomposing industrial wastes -involved in elemental cycles -important links in food chains -live in intestinal tracts ofanimals where they aid in the digestion of food, and produce substances that are valuable to host animal -are essential in various food and beverage industries -used to produce certain enzymes and chemicals -as a source of antibiotics -essential in field of genetic engineering -used as "cell models" -cause infectious diseases and microbial intoxications
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| infectious disease |
-a pathogen colonizes a person's body -pathogen causes disease |
| microbial intoxication |
-a pathogen produces a toxin in vitro (outside the body) -a person ingests the toxin -toxin causes the disease |
| Difference in infectious disease and microbial intoxication |
Infectious diseases result when a pathogen inhabits the body and subsequently causes disease. Micorbial intoxications result when a person ingests a toxin (poisonous substance) that has been produced by a pathogen outside the body. |
| explain the relationship between microbes and infectous diseases |
| microbes cause infectous diseases |
| Leeuwenhoek |
-first person to see live bacteria and protozoa -"Father of Microbiology" (or Protozoology) - single-lens microscopes or simple microscopes |
| Pasteur |
-discovered the process of alcoholic fermentation -discovered forms of life that could exist in the absence of oxygen (anaerobes) -developed a process to kill microbes that were causing wine to spoil- pasteurization -made significant contributions to the germ theory of disease - discovered infectious agents that caused silkworm diseases and how to prevent them -changes in hospital practices to minimize the spread of disease by pathogens -developed vaccines to prevent chicken cholera, anthrax, and swine erysipelas -developed vaccine to prevent rabies in dogs and treat human rabies |
| Koch |
-Koch's Postulates -contributions to the scientific theory of disease -discovered B anthracis produces spores capable of resisting adverse conditions of anthrax -developed methods of fixing, staining, and photographing bacteria -developed methods of cultivating bacteria on a solid media, thus obtaining pure cultures -discovered the bacterium that causes tuberculosis and the one that causes cholera -lead to a skin test valuable in diagnosing tuberculosis |
| abiogenesis vs biogenesis |
abiogenesis is the idea that life can arise spontaneously from nonliving material. Biogenesis is the theory that life can only arise from preexisting life. |
| germ theory of disease |
| Koch's Postulates |
| 1. the microorganism must always be found in similarly diseased animals but not in healthy ones 2. The microorganism must be isolated from a diseased animal and grown in pure culture. 3. The isolated microorganism must cause the original disease when inoculated into a susceptible animal 4. The microorganism can be reisolated from the experimentally infected animal |
| exceptions to Koch's Postulates |
| simple microscope |
| microscope containing only one lens 3-20x mag. |
| compound light microscope |
| microscope with more than one lens that uses visible light as source of illumination -ocular x objective to get magnification -oil-immersion= 1000x |
| electron microscope |
| -use electron beam as source of illumination and magnets to ficus the beam -have greater resolving power than CLM -can NOT be used to observe living organisms; they are killed during the specimen-processing procedures -both types have built in camera systems |
| types of electron microscopes |
| -Transmission electron microscope- has tall column at the top of which an electron gun fires a beam of electrons downwards; .2nm resolving power; 1 million x mag. -Scanning electron microscope- shorter column and specimen is placed at bottom of column; used to observe outer surfaces of specimens; 20 nm resolving power |
| Atomic Force microscope (AFM) |
| enables scientists to observe living cells at extremely high mag. and resolution under physiological conditions -provides a true 3D surface profile |
| types of Compound light microscopes |
| -brightfield- object against a brigh background -darkfield- object is illuminated against a dark background -phase-contrast microscope- observe unstained living microorganisms -fluorescence microscope- built in UV light source, emits longer wavelength of light, causing object to glow against dark background (type of immunodiagnostic procedure) |
| cell theory |
| scientific conclusion that all plant and animal tissues are composed of cells |
| cell membrane function |
| -encloses and holds cell intact, separating contents of cell from outside world ("skin") -allows only certain substances to pass through it, regulating the passage of nutrients, waste products, and secretions into and out of cell= selective permeability -aka plasma mem or cytoplasmic mem |
| nucleus function |
| -controls functions of entire cell -"command center of cell" |
| ribosome function |
| -site of protein synthesis |
| Golgi complex function |
| -connects or communicates with ER -completes the transformation of newly synthesized proteins into mature, functional ones and packages them into small, membrane-enclosed vesicles for storage w/in the cell or export outside the cell (exocytosis or secretion) -"packaging plant" |
| lysosome function |
| -contain lysozyme and other digestive enzymes that break down foreign material taken into the cell by phagocytosis -aid in breaking down worn out parts of the cell and may destroy the entire cell if the cell is damaged or deteriorating (autolysis) |
| mitochondrial function |
| - where most ATP molecules are formed by cellular respiration -"power plant of cell" |
| plastid function |
| -site of photosynthesis (conversion of light energy into chemical energy) |
| cytoskeleton function |
| -strengthens, supports, and stiffens the cell to give it its shape |
| Eucaryotic cell wall function |
| provides rigidity, shape, and protection for cell |
| flagella |
| -the whipping motion of flagella allows cells to swim through liquid environments -organelle of locomotion |
| cilia |
| -organelle of locomotion -beat with a coordinated, rhythmic movement |
| chromosome function |
| -control center of bacterial cell -can duplicate itself, guide cell division, and direct cellular activities |
| Procaryotic cell wall function |
| -same function as euk; provide rigidity, shape and protection -is much more chemically complex than euk |
| capsule function |
| -serve an antiphagocytic function, protecting the encapsulated bacteria from being ingested (phagocytized) by phagcytic white blood cells |
| Procaryotic flagella function |
| -enable bacteria to move -number and arrangement can be used for classification and identification purposes -bacteria possess flagella, never cilia |
| pili function |
| -not associated w/ motility; organelles of attachment -one type enables bacteria to adhere or attach to surfaces -other type enables transfer of genetic material from one bacterial cell to another following attachment of cells to each other |
| endospore function |
| -enable bacteria to survive adverse conditions, such as temp extremes, dessication, and lack of nutrients |
| genus |
| first part in name of a species |
| specific epithet |
| 2nd part in name of a species -cannot be used alone |
| species |
| specific member of a given genus |
| Hooke |
-first person to use the term "cells" -small, empty chambers in the structure of cork= cell |
| Schleiden and Schwann |
| -concluded that all plant and animal tissues were composed of cells= cell theory |
| Virchow |
| -proposed the theory of biogenesis= that life can arise only from preexisting life, and cells only from preexisting cells |
| characteristics used to characterize viruses |
1. type of genetic material (DNA vs RNA) 2. shape of capsid 3. number of capsomeres 4. size of capsid 5. presence or absence of an envelope 6. type of host that it infects 7. type of disease it produces 8. target cell 9. immunologic or antigenic properties |
| 5 properties that distinguish viruses from bacteria (or living cells) |
1. have either DNA or RNA, not both like living cells 2. unable to replicate on their own, must invade a host cell 3. do not divide by binary fission, mitosis, or meiosis 4. lack the genes and enzymes necessary for energy production 5. depend on ribosomes, enzymes, and metabolites of host cell for protein and nucleic acid production |
| 3 viral diseases in humans |
-HIV -meningitis -measles -mumps -influenza
|
| viroid vs virion |
viroid- infectious RNA molecule -cause plant diseases virion- complete viral particle -can infect humans, animals, plants, fungi, protozoa, algae, and bacterial cells |
| ways to classify bacteria |
1. gram-negative 2. gram-positive 3. those that lack a cell wall or -can classify on the basis of their relationship to oxygen and CO2 |
| purposes of fixation |
1. kills the organisms 2. preserves their morphology (shape) 3. anchors smear to the slide |
| diplococci |
| pairs of cocci |
| streptococci |
| chains of cocci |
| staphylococci |
| clusters of cocci |
| octads |
| packets of 8 cocci |
| tetrads |
| packets of 4 cocci |
| coccobacilli |
| elongated bacilli (rods) |
| diplobacilli |
| pairs of bacilli |
| streptobacilli |
| chains of bacilli |
| pleomorphism |
| bacterial species with the ability to exist in a variety of shapes |
| obligate aerobe |
| require an atmosphere containing about 20% oxygen to grow and multiply |
| microaerophiles |
| require reduced oxygen concentrations (about 5%) |
| obligate anaerobe |
| can only grow in an aerobic environment (no oxygen) |
| aerotolerant anaerobe |
| -does not require oxygen -grows better in the absence of oxygen -can survive in atmospheres containing oxygen |
| facultative anaerobe |
| -capable of surviving in either the presence or absence of oxygen |
| capnophiles |
| grow better in the lab with an atmosphere containing 5%-10% CO2 |
| bacterial diseases in humans |
-Pneumonia -nongonococcal urethritis (NGU) -Rocky Mountain Spotted Fever |
| how archaea are diff from bacteria |
-more closely related to procaryotes -many are extremeophiles (live in extreme environments) -cell walls have no peptidoglycan -diff in rRNA structure |
