Microbiology Final Exam Review – Flashcards

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purpose of studying microbiology
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1. microorganisms affect human health 2. microorganisms are essential in all life cycles 3. microbes are used in food production
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benefits of studying microbiology
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understanding the world around us- everything is covered in microbes
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microbiology
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the study of microorganisms
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bacteria
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all prokaryotic organisms
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algae
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photosynthesis; eukaryotic organisms in the kingdoms Protista and Plantae
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fungi
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the kingdom of non-photosynthetic eukaryotic organisms that absorb nutrients from their environment
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viruses
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obligate intracellular parasites; composed of a nucleic acid core inside a protein coat
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protozoa
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single-celled, microscopic, animal-like protists in the kingdom Protista
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site of employment of microbiologists
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a. university- teaching, researching, raining students b. commercial laboratories- developing microbes used in genetic engineering c. health professions- clinical laboratories performing tests to diagnose disease or determining which anitbiotics will cure a particular disease d. hospital/gov't labs- controlling spread of infection and related public health matters
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Hippocrates
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Greek physician who lived around 400 B.C. He associated particular signs and symptoms with certain illnesses and realized that disease could be transmitted from one person to another by clothing or other objects.
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Hooke
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built a compound microscope (one in which light passes through two lenses) and used it to observe thin slices of cork; he coined the term cell; 1664
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Leeuwenhok
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Dutch cloth merchant and amateur lens grinder, who first made and used lenses to observe living microorganism; his lenses gave magnifications up to 300X; everywhere he looked he found animalcules and observed all the major kinds of microorganisms; he refused to sell his microscopes to others and so failed to foster the development of microbiology; 1684
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cell theory
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Theory formulated by Schleiden and Schwann that cells are the fundamental units of all living things
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bubonic plague
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a bacterial disease, transmitted by flea bites, spreads in the blood and lymphatic system
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germ theory of disease
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microorganisms can invade other organism and cause disease
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spontaneous generation
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theory that living organisms can arise from nonliving things
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Aristotle
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proposed spontaneous generation
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Redi
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refuted spontaneous generation with his meat experiments (people thought rotten meat grew maggots. He placed 3 pieces of meat in an open jar, a sealed jar, and a jar covered with gauze. No maggots grew in the sealed jar, howeversome did hatch from fly eggs laid in the gauze)
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Pasteur
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1. disproved spontaneous generation with his swan-necked flasks 2. discovered that selected yeast made good wine, but mixture of other microorganisms comped with the yeast for sugar and made wine taste oily or sour, and developed pasteurization to kill unwanted organisms as a result; 3. identified three different microoganisms that each caused a different disease in silkworms, which was a step in proving the germ theory of disease 4. created/ discovered the rabies vaccine (made of dried spinal cord from rabbits infected with rabies); got this idea when his assistant accidentally used an old chicken cholera culture to inoculate some chickens and later inoculated them with a fresh chicken cholera culture and they remained healthy 5. was director of the Pasteur Institute, where he guided the training and work of other scientists 6. associated specific organisms with specific diseases
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Koch's postulates (general)
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four postulates formulated by Robert Koch in the 19th century; used to prove that a particular organism causes a particular disease
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Koch's postulats (specific)
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1. The specific causative agent must be found in every case of the disease 2. The disease organism must be isolated in pure culture 3. Inoculation of a sample of the culture into a healthy, susceptible animal must produce the same disease 4. The disease organism must be recovered from the inoculated animal.
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Semmelweis
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recognized the connection between autopsies and puerperal (childbed) fever- scientists would conduct an autopsy and then help a woman deliver without washing their hands; he was ridiculed for his ideas and eventually had a nervous breakdown; associated with sanitation
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Lister
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initiated the use of dilute carbolic acid on bandages and instruments to reduce infection (the first aseptic techniques) after reading of Pasteur's and Semmelweis's work; considered the father of antiseptic surgery
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immunology
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study of specific immunity and how the immune system responds to infectious agents
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Jenner
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realized that people who got cowpox didn't get smallpox; he inoculated his son and another child first with cowpox and then with smallpox, both lived (first vaccine); he received grants to continue his work, probably the first grants for medical research
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Reed/yellow fever
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identified virus causing yellow fever, transmitted by mosquitoes
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chemotherapy
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use of chemical substances to treat various aspects of disease
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Ehrlich
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1. discovered that certain dyes stained microorganisms but not animal cells, suggesting that the dyes or other chemicals might selectively kill microbial cells. This gave him the idea of a "magic bullet," a chemical that would destroy specific bacteria without damaging surrounding tissues 2. found arsenophenylglycine to be effect against sleeping sickness 3. found Salvarsan to be effective against syphilis (the only treatment for the next 40 years)
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Griffith
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discovered that previously harmless bacteria could change their own nature and become capable of causing disease; esp. remarkable that live bacteria were shown to acquire heritable traits from dead ones
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Human Genome Project
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1. Identified location and chemical sequence of genes on human chromosome 2. Microbes helped read the human genome 3. 113 genes in the human genome come from bacteria
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Waksman
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examined soil samples from all over the world for growth-inhibiting microorganisms or their products. He finally managed to isolate streptomycycin, which constituted a major breakthrough in the treatment of tuberculosis. He also isolated neomycin, chlorampheniocol, and chlotetracycline. He also coined the term antibiotic.
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evolution of the microscope
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One Lens--> Light Microscope--> Electron Microscope
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units of measurements
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meter (m) centimeter (cm) millimeter (mm) micrometer (μm) nanometer (nm) angstrom (Å)
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resolution
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ability of an optical device to show two items as separate and discrete entities rather than a fuzzily overlapped image
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wavelength
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distance between successive crests or troughs of a light wave
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numerical aperture
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the widest cone of light that can enter a lens
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resolving power
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A numerical measure of the resolution of an optical instrument (λ/ 2NA)
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total magnification
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Obtained by multiplying the magnifying power of the objective lens by the magnifying power of the ocular lens
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transmission
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passage of light through an object
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reflections
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bouncing of light off an object
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absorption
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attachment of the virus to the host cell in the replication process
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luminescence
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process in which adsorbed light rays are reemitted at longer wavelengths
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fluorescence
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emission of light of one color when irradiated with another shorter wavelength of light
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phosphorescent
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continued emission of light by an object when light rays no longer strike it
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diffraction
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phenomenon in which light waves, as they pass through a small opening, are broken up into bands of different wavelengths
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refraction
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the bending of light as it passes from one medium to another of a different density
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immersion oil
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Substance used to avoid refraction at a glass-air interface when examining objects through a microscope: same refractive index as glass- doesn't work w/ plastic
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base
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supporting structure, contains light source
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condenser
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converges light beams to pass through specimen
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iris diaphragm
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controls the amount of light passing through the specimen
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objective lens
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lens in a microscope closest to the specimen that creates an enlarged image of the object viewed
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body tube
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transmits light to ocular lens
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ocular lens
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lens in microscope that further magnifies the image from the objective lens
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mechanical stage
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allows precise control in moving the slide
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coarse adjustment
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knob to locate specimen
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fine adjustment
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brings specimen into focus
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bright-field illumination
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illumination produced by the passage of visible light through the condenser of a light microscope
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dark-field illumination
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in light microscopy the light that is reflected from an object rather than passing through it, resulting in a bright image on a dark background
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phase-contrast
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use of a microscope having a condenser that accentuates small differences in the refractive index of various structures within the cell
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fluorescence microscopy
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use of ultraviolet light in a microscope to excite molecules so that they release light of different colors; flurochrmoe used so specimen stands out from dark background; fluorescent antibody staining determines if antibody is present
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Normarski microscopy
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aka differential interference contrast microscopy; utilizes differences in refractive index to visualize structures, producing a nearly 3D image
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electron microscopy
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uses a beam of electrons rather than a beam of light and electromagnets instead of glass lenses to produce an image, allows whole specimens to be viewed in 3D; includes TEM, SEM, STMs
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scanning electron microscopy
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uses electron bean and electromagnetic lenses, gives a 3D view of surfaces, is useful for observation of exterior surfaces of cells or of internal surfaces
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wet mount slide
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microscopy technique in which a drop of fluid containing the organisms (often living) is placed on a slide
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hanging drop
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a special type of wet mout often used with dark-field illumination to study motility of organisms
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smear
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a thin layer of liquid specimen spread out on a microscopic slide
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stain
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aka dye; a molecule that can bind to a structure and give it color
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simple stain
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single dye used to reveal basic cell shapes and arrangements
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differential stain
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Use of two or more dyes to differentiate among bacterial species or to distinguish various structures of an organism; for example, the Gram Stain
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Gram Stain
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A differential stain that uses crystal violet, iodine, alcohol, and safranin to differentiate bacteria. Gram-positive bacteria stain dark purple; Gram-negative ones stain pink/red
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spore stain (Schaeffer-Fulton)
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stain which allows visualization of spores easily within a cell. Heat-fixed smears are covered with malachite green and then gently heated until they steam. 5 minutes of such steaming causes the endospore walls to become more permeable to the dye. The slide is then rinsed w/ water for 30 seconds to remove the green dye from all parts of the cell except for endospores, which retain it. Then a counterstain of safranin is placed on the slide to stain the non-spore-forming areas of the cells.
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Acid-Fast Stain
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detects acid fast organisms like tuberculosis and leprosy
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negative stain
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Technique of staining the background around a specimen, leaving the specimen clear and unstained
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flagellar stain
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A technique for observing flagella by coating the surfaces of flagella with a dye or a metal such as silver
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obligate intracellular parasites
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an organism or virus that can live or multiply only inside a living host cell
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capsid
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protein coating of a virus, which protects the nucleic acid core from the environment and usually determines the shape of the virus; composed of capsomeres
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nucleocapsid
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the nucleic acid and capsid of an virus
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virion
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a complete virus particle, including its envelope if it has one
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genome
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the genetic information contained in the DNA of an organism
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envelope
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a bilayer membrane found outside the capsid of some viruses, acquired as the virus buds through one of the host's membrane
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spike
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a glycoprotein projection that extends from the viral capsid or envelope and is used to attach to or fuse with host cells
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RNA
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viral genetic material
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virion
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A complete virus particle, including its envelope if it had one
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capsid
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The protein coating of a virus which protects the nucleic acid core from the environment and usually determines the shape of the virus
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host range
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the different types of organisms that a microbe can infect
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specificity
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the property of a virus that restricts it to specific types of host cells
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rhinoviruses
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a virus that replicates in cells of the upper respiratory tract and causes the common cold
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retroviruses
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An enveloped RNA virus that uses its own reverse transcriptase to transcribe its RNA into DNA in the cytoplasm of the host cell
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adenoviruses
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A medium-sized, naked DNA virus that is highly resistant to chemical agents and often causes respiratory infections or diarrhea
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herpesviruses
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DNA virus that can remain latent in host cells for long periods of time
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virioids
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An infectious RNA particle, smaller than a virus and lacking a capsid that causes various plant diseases
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prions
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An exceedingly small infectious particle consisting of protein without nucleic acid
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adsorption
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attachment of the virus to the host cell in the replication process
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penetration
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The entry of the virus or its nucleic acid into the host cell in the replication process
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synthesis
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viral replication step in which new nucleic acids and viral proteins are made
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maturation
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The process by which complete virions are assembled from newly synthesized components in the replication process
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release
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The exit from the host cell of new virions which usually kill the host cell
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bacteriophage
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a virus that infects bacteria
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recognition factors
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factors that cause the body to recognize antigens and produce antibodies, involves viral exterior
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growth curve
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the different growth periods of a bacterial or phage population; includes lag phase, log phase, and stationary phase
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eclipse period
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Period during which viruses have absorbed to and penetrated host cells but cannot yet be detected in cells
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accumulation period
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during replication cycle viruses are undetected from exterior b/c are accumulating in the cell
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rise period
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during replication cycle, viruses are maturing and being released
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culturing methods
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•Subculturing: cells from existing culture are transferred to new containers with fresh nutrient media •Cell suspensions forming monolayers which can be subcultured (tissue culture today cell culture)
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primary cell cultures
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A culture that comes directly from an animal and is not subcultured
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continuous cell lines
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Cell culture consisting of cells that can be propagated over many generations
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teratogen
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An agent that induces defects during embryonic development
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