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microbiology #2

test 2

aggregation of cells arising from single parent cell Colony
collection of microbes living on a surface in a complex community biofilm
source of Carbon (CO2) for growth requirements Autotroph, heterotrophs (organic compounds)
sources of energy for growth requirements chemotrophs (chemicals)(organism use), phototrophs (light) (plant use)
grow in the presence of oxygen aerobes
an organism that cannot tolerate oxygen Anaerobes
microorganism that can live with or without oxygen facultative anaerobe
microorganism with which prefers anaerobic conditions but can tolerate exposure to low levels of oxygen aerotolerant anaerobe
microorganism that require requires low levels of oxygen microareophile
anabolism ceases because of insufficient _____ nitrogen
chemical requirements for growth nitrogen, phosphorus, sulfur, trace elements, growth factors
required in minute amounts for the growth requiremnts trace elements
necessary organic chemicals that cannot be synthesized by certain organisms growth factors
used by mycoplasmas (bacteria) for cell membranes cholesterol for growth factors
component of proteins amino acids for growth factors
functional portion of cytochromes in electron transport system heme for growth factors
precursor of NAD and NADP niacin (nicotinic acid, vitamin B3) for growth factors
component of coenzyme A Pantothenic acid (vitamin B5) for growth factors
precursor of folic acid, which is involved in metabolism of one carbon compounds & nucleic acid synthesis para-aminobezoic acid (PABA) for growth factors
components of nucleic acids purines, pyrimidines for growth factors
utilized in transamination syntheses of amino acids pyridoxine (vitamin B6) for growth factors
precursor of FAD riboflavin (vitamin B2) for growth factors
utilized in some decarboxylation reactions thiamine (vitamin B1) for growth factors
temperature affects what in proteins? the 3D structure
what is temperature sensitive in a cell? lipid containing membranes of cells & organelles
if temperature is too low in cell, what happens? membranes become rigid & fragile
if temperature is too high in cell, what happens? membranes become too fluid
what is the ideal temperature for bacteria? 37C
most humans and pathogens are classifed as? mesophiles
organisms are sensitive to change in what kind of environment? acidity
neutrophiles have what kind of pH? neutral
acidophiles have what kind of pH? low pH
alkalinophiles have what kind of pH? High pH
pressure exerted on a semipermeable membrane by a solution containing solutes that cannont freely cross membrane osmotic pressure
lower solute concentrations, cells swell hypotonic solution
greater solute concentration, cell shrivels hypertonic solution
restricts organisms to certain environments, obligate & facultative halophiles physical effects of water
cell is normal, fluid is equal on the inside and the outside isotonic solution
a microbe harms another organism antagonistic relationship
members of an association receive benefits that exceed those that would result if each lived by itself synergistic relationship
organisms become interdependent and rarely live outside the relationship symbiotic relationship
complex relationships among numerous microorganisms, form on surfaces, medical devices, mucous membranes of digestive system, dental plaque is considered this biofilm
progenitor is termed a________ colony forming unit (CFU)
pure cultures are composed of cells arising from a single ______ progenitor
_______technique prevents contamination of sterile substances or objects Aseptic
2 common isolation techniques streak plates, pour plates
Bacterial inoculum intoduced into nutrients called ____ media
only _____ of bacteria are culturable 5%
6 types of culture media defined, complex, selective, differential, anaerobic, transport media
medium in which the exact chemical composition is known defined media
exact chemical composition is unknown, contains nutrients from yeast, beef, soy or proteins, supports growth of wide variety of microorganisms, used to culture organisms with unknown nutritional needs complex media
allows certain types of organisms to grow, and inhibits the growth of other organisms selective media
Mannitol Salt Agar (MSA) has a high salt content, which represses the growth of bacteria other than _______ Staphylococci
differentiate closely related species of bacteria, organisms will produce characteristic changes or growth patterns that are used for identification or differentiation differential media
Blood agar (BAP) visualizes the ability of bacterial species to____ lyse red blood cells
crystal violet kills ______ gram positive bacteria
e. Coli is usually Gram _______ negative
obligate anaerobes must be cultured in the absence of free oxygen anaerobic media
petri plates are incubated in ____________ culture vessels, sealable containers that contain chemicals that reduce the oxygen anaerobic
which is th emost common anaerobic? Palladium
used by hospital personnel to ensure clinical specimens are not contaminated and to protect people from infection, rapid transport of sample is important transport media
examples of transport media blood culture bottles, thioglycollate broth
stores for short period of time refrigeration
stores for years deep-freezing
bacteria freeze better in the presence of what? glycerol
freeze drying in to a powder, stores for decades lyophilization
time required for a bacterial cell to divide/ grow, dependent on chemical & physical conditions generation time
microbial growth curve lag phase, log (exponential) phase, stationary phase, death (decline) phase
direct methods not requiring incubation microscopic counts
stained prokaryotes & large eukaryotes microscopic counts
electronic counters for measuring microbial reproduction flow cytometry, coulter counter
direct methods require _____ incubation, serial dilution & viable plate counts
indirect methods require ______ turbidity
what is turbidity measured by? spectrophotomoeter
what can grow in a petri plate ona laboratory table? an aerobic bacterium
This statement "in the laboratory, a sterile inoculating loop is moved across the agar surface in a culture dish, thinning a sample and isolating individuals" describes which of the following? streak plate
superoxide dismutase neutralizes ____ singlet oxygen
the most reactive of the 4 toxic forms of oxygen is? the hydroxyl radical
microaerophiles that grow best with a high concentration of carbon dioxide in addition to a low level of oxygen are called? capnophiles
organisms that preferentially thrive in icy waters are described as _______ psychrophiles
barophiles cannot ______ cause disease in humans
an organism that cannot exist in the presence of oxygen obligate anaerobe
when the exact chemical composition is know it is called a ? defined medium
most useful in representing population growth on a graph semilogarithmic graph using a log scale on the y-axis
best method for counting fecal bacteria from a stream to determine the safety of the water for drinking membrane filtration
a device that directly counts microbes as they pass through a tube in front of an electronic detector coulter counter
the ability to respond to changes in population density quorum sensing
what do cells require for a redox reaction? electrons
toxic form of oxygen, molecular oxygen with electrons that have been boosted to a higher energy state singlet oxygen
what essential element do all cells recycle from amino acids & nucleotides? nitrogen
what are small organic molecules that are required in minute amounts for metabolism growth factors
the lowest temperature at which a microbe continues to metabolize is called its _________ minimum growth temperature
__________ pigments protect many phototrophic organisms from photochemically produced singlet oxygen carotenoid
microbes that reduce to N2 to NH3 engage in nitrogen __________ fixation
a student observes a researcher streaking a plate numerous times, flaming the loop between streaks. The researcher is likely using the ______ method to isolate microorganisms streak plate
chemolithotrophs acquire electrons from ________ compounds inorganic
destroys most microorganisms & viruses on non-living tissues (particularly pathogens) Disinfection
destruction of ALL microorganisms on an object sterilization
sterile microbial control disinfection & sterilization
reduction in the microorganisms & viruses on living tissues (particularly pathogens) antiseptic
mechanical removal of microorganisms (handwashing) Degerming
using heat to destroy pathogens & reduce microbial load in food products, slows down food spoilage pasteurization
reduction of pathogens from objects to meet public health standards sanitation
most resistant to sterilization prions
least resistant to sterilization enveloped viruses
what biosafety level: handling microbes that do not cause disease in humans, ex: yogurt factories BSL-1
bio-safety level: handling moderately hazardous agents BSL-2
bio-safety level: all manipulations of microbes done in safety cabinets BSL-3
denature proteins, interfere with integrity of cytoplasmic membrane & cell wall, disrupt structure & function of nucleic acids effects of high temperature on cells
used to disinfect, sanitize, sterilize & pasteurize, denature proteins & destroys cytoplasmic membranes, more effective than dry heat moist heat
kills vegetative cells boiling
methods of microbial control using moist heat boiling, autoclaving, pasteurization
high heat, high pressure, over boiling autoclaving
autoclave conditions 121C, 15 psi, at least 15 minutes
heat destroys pathogens, reduces the number of spoilage micoorganisms in food, not sterilization pasteurization
decreases, microbial metabolism, growth & reproduction, refrigeration halts growth of most pathogens, some microbes can multiply in refrigerated foods refrigeration & freezing
_______ inhibits growth as a result of removal of water Desiccation (drying)
_______ is used for long term preservation of microbial cultures, prevents formation of damaging ice crystals Lyophilization
pass non-sterile solution through a membrane with small pores that trap microbial contaminents filter sterilization
introduces so much DNA damage that the cell dies, superficial sterilization, not common in hospitals only works on surfaces non-ionizing radiation/ UV radiation
commonly used in the healthcare setting, labs & homes, have disagreeable odor & possible side effects, ex: pine-sol phenol & phenolics
swabbing skin with _____ prior to injection removes most microbes, ex: ethanol, isopropanol alcohol
iodine tablets, iodophores, chlorine treatment, bleach, the addition of fluoride to water & toothpaste, are all examples of what halogens
hydrogen peroxide can disinfect & sterilize surfaces, not useful for treating open wounds oxidizing agents
good degerming agent, but not antimicrobial soaps & detergents
heavy metals used for disinfection silver nitrate
______ is commonly used to prevent blindness in newborn babies caused by N. gonorrhoeae silver nitrate
________ contains 1 molecule of mercury, and is used to preserve vaccines Thimerosal
Formalin is considered a ______ Aldehyde
________ is used in embalming & in disinfection of rooms & instruments Formalin
methods for evaluating disinfectants and antiseptics in-use test
accurate determination of proper strength and application procedure for each specific situation in-use test
what kills microorganisms on laboratory surfaces? disinfectants
what best describes the disinfecting of cafeteria plates? sanitization
the microbial death rate is used to measure the efficiency of ________ detergent, antiseptics and sanitization techniques
the endospores of which organism are used as a biological indicator of sterilzation bacillus stearothermophilus
what functions as an auotclave? pressure cooker
the preserve beef jerky from microbial growth relies on which method? desiccation
which type of radiation is more widely used as antimicrobial technique? electron beams
what substances would most effectively inhibit anaerobes? hydrogen peroxide
what adjective best describes a surgical procedure that is free of microbial contaminants? aseptic
a sample of E. coli has been subjected to heat for a specified time, and 805 of the cells have been destroyed, what best describes this event? decimal reduction time
what is active against bacterial endospores? ethylene oxide
what disinfectant acts against against cell membranes? phenol
what disinfectant contains alcohol? tincture of bromine
what antimicrobial chemical has been used to sterilize spacecraft? ethylene oxide
what class of surfactants is most soluble in water? quaternary ammonium compounds
who invented penicillin? Alexander Flemming
effective antimicrobial agent that is more toxic to the pathogen than to the host selective toxicity
numerous differences between _________ bacteria and ________ hosts provides many targets pathogenic, eukaryotic
Beta-lactams: penicilin, cephalosporin, carbapenem, vancomycin, bacitracin inhibit what? this also weakens the cell wall peptidoglycan formation
antimicrobial agent that inhibits protein synthesis by blocking the tRNA docking site tetracycline
antimicrobial agent that inhibits protein synthesis by changing the shape of the 30s ribosomal subunit aminoglycoside
what is a good target for antimicrobial activity? ribosomes
why are ribosomes a good target for antimicrobial activity? changes shape of subunits within ribosomes to interfere with binding, prevent elongation of proteins & prevents enzymatic activity
_________ attaches to ergosterol in fungal membranes, forming pores which disrupts the cytoplasmic membrane Amphotericin B
what is effective when pathogen and host metabolic processes differ? Antimetabolic agents
structurally similar to an enzyme required to synthesize folic acid, necessary to make DNA & RNA nucleotides sulfonamides
what happens when you over prescibe broad spectrum drugs? antibiotic resistance
example of a broad spectrum drug sulfonamides, erythomycin, tetracyline
bacterial lawn exposed to dics impregnated with antimicrobial agents, the larger the zone of inhibition the more effective kirby-bauer disk diffusion
the lowest concentration of antimicrobial able to kill all bacteria in a well minimum inhibitory concentration (MIC)
routes of administration for antimicrobial drugs topical application, oral route, intramuscular administration, intravenous administation
side effects of administration of antimicrobial drugs toxicity, allergies, disruption of normal microbiota
why must you finish a course of prescribed antibiotics because of the development of resistance in populations
________ denatures Beta-lactam penicillins making it ineffective Beta-lactamase
_______ remove drugs from inside of the cell efflux pump
forming an enzyme that destroys or deactivates the drug will... alter the target of the drug, efflux pumps remove drugs from inside the cell, slow down metabolism, which creates fewer targets, alter the binding site of the drug
Alters penicillin-binding protein in the membrane Gene encoded on a plasmid S. aureus mecA gene
Proteins that traverse the inner and outer membrane – remove antibiotic from the cell Genes encoded on plasmids
Bacterial cells in biofilm become “sessile”, or metabolically inactive – decreases drug targets available, If a cell reverts to metabolic activity, becomes susceptible again Slow down metabolism
Genotypic changes, Polymicrobial infections increase genetic transfers between species Antibiotic resistance
Phenotypic changes, Sessile cells are metabolically inactive, Transient tolerance Antibiotic tolerance
Maintain high concentration of drug in patient for sufficient time, Use antimicrobial agents in combination, Use antimicrobials only when necessary, Develop new variations of existing drugs, Search for new antibiotics Retarding Resistance
diffusion/ dilution tests that expose pathogens to antimicrobials are designed to ________ determine which drug is most effective against a particular pathogen & determine the amount of a drug to use against a particular pathogen
ina kirby-bauer susceptibility test, the presence of a zone of inhibition around disks containing antimicrobial agents indicates________ that the microbes does not grow in the presence of the agents
the key to successful chemotherapy is _______ selective toxicity
why are sulfonamides effective? humans & microbes use PABA differently in their metabolism
resistance to one antimicrobial agent because of its similarity to another antimicrobial agent cross resistance
multiple drug resistant microbes ________ frequently develop in hospitals
what is most closely associated with a beta-lactam ring? penicilin
drugs that act against protein synthesis aminoglycosides
drugs that neutralize the acidity of ________ prevent viral uncoating phagolysosomes
___________ can be used to stop microbial replication nucleotide analogs
drugs containing __________ retard viral growth by blocking the reproduction of essential viral proteins protease inhibitors
PABA is used to ________ synthesize folic acid
the interplay between drugs that results in efficacy that exceeds the efficacy of either drug alone Synergism
most numerous & diverse group of cellular microbes, thrive in various habitats, only a few are capable of colonizing humans & causing disease prokaryotes
what bacteria are endospores produced by? bacillus & clostridium
defensive strategy against unfavorable conditions, are often difficult to kill endospores
how do prokaryotes reproduce? asexually (binary fission)
2 types of asexual reproduction done by prokaryotes? binary fission (most common) & budding (usually done by fungi)
modern prokaryotic classification is based on? genetic relatedness of rRNA sequences
three domains of prokaryotic classifcation archaea, bacteria, eukarya
lack true peptidoglycan, cell membrane lipids have branched hydrocarbon chains common features of archaea
what is not known to cause disease? archaea
2 types of extremophiles thermophiles, halophiles
DNA, RNA, cytoplasmic membranes & proteins do not function well below 45C thermophiles
inhabit extremely saline habitats, depend on greater that 9% NaCl to maintain integrity of cell walls, may contain red or orange pigments halophiles
largest group of archaea, convert carbon dioxide, hydrogen gas & organic acids to methane gas Methanogens
live in the colons of cows, primary source of environmental methane methanogens
Different types of gram positive bacteria: Firmicutes clostridium, mycoplasma, bacili
Different types gram positive bacilli bacteria bacillus, listeria, lactobacillus, streptococcus, staphylococcus
Different types of gram positive actinobacteria corynebacterium, mycobacterium, actinomyces, nocarida, streptomyces
rod shaped, obligate anaerobes, produce toxins that cause disease in humans, endospores survive harsh conditions clostridia
clostridia is associated with what bacteria/ diseases Cdiff, tetanus, botulism
what is also know as "walking pnemonia" or pnemonia acquired during the summer? mycoplasma pneumoniae
smallest free living cells, lack cell walls mycoplasmas
this gram positive bacteria is classified as endospore forming aerobes and facultative anaerobes bacillus
contaminates milk/ meat products, capable of reproducing under refrigeration, can kill the fetus in pregnant women if it crosses the placenta listeria monocytogenes
grows in the mouth, stomach, intestinal tract & vagina, rarely causes disease, inhibits the growth of pathogens within the body, used in the production of various foods Lactobacillus
Streptococcus pyogenes "group A" can cause ______ strep throat or necrotizing fascitis
Streptococcus agalactiae "Group B" can cause ________ newborn meningitis
Staphylococcus epidermidis can cause ______ commensal skin colonizer
Staphylococcus aureus is _________ common pathogen, multi-drug resistant (MRSA, VRSA)
what does the gram positive bacteria: corynebacterium diptheriae cause? diptheria-throat infection
filamentous rods, slow growth partly due to mycolic acid in its cell walls mycobacterium
mycobacterium tuberculosis is called? TB
mycobacterium leprae is called? leprocy
the gram positive bacteria actinobacteria is also known as? phylum
form branching filaments resembling fungi, producers of antiniotics, acid-fast actinobacteria (phylum)
examples of actinobacteria actinomyces, nocardia, streptomyces
produces numerous antibiotics streptomyces
largest and most diverse group of bacteria proteobacteria
proteobacteria is gram_______ negative
5 classes of proteobacteria alpha, beta, gamma, delta, epsilon -proteobacteria
associated with plants, nitrogen fixation rhizobium
spread by arthropods, associated with rocky mountain spotted fever rickettsia
can contaminate milk, causes miscarriges, cause brucellosis Brucella
rhizobium, rickettsia & brucella are all categorized as what gram-negative bacteria alphaproteobacteria
causes gonorrhea & meningitis neisseria
causes pertussis "whooping cough" bordetella
legionella, enterobacteriacae & psuedomonads are all categorized as what gram negative bacteria? gammaproteobacteria
what gram-negative bacteria causes legionnaire's disease, american legion legionella
what gram-negative bacteria causes intestinal bacteria to develop? enterobacteriacae
what gram-negative bacteria is associated with important human pathogens? psuedomonads
what does the gram negative bacteria vibrio parahaemolyticus cause? "summer diarrhea" oysters
what does the gram negative bacteria yersinia pestis cause? plague, black death
what gram negative bacteria causes urinary tract infections, wound infections, respiratory infections, bacteremia, ear infections psuedomonas aeruginosa
infects the stomach, causes ulcers, stomach cancer hylicobacteria pylori
hylicobacteria pylori is classified as what class of bacteria? epsilonproteobacteria
venereal disease, causes neonatal blindness chylamydia trachomatis
what gram negative bacteria is chylamydia trachomatis classified as? phylum chlamydiae
the bacteria that causes syphilis, neurosyphilis treponema pallidum
lyme disease, spread through ticks borrelia
what 2 bacteria are classified as phylum spirochetes? treponema pallidum & borrelia
what bacteria lacks peptidoglycan cell walls? Chylamydia
Archaea are classified into phyla based primarily ______ sequences rRNA
________ inhibit extremely saline habitats, such as the Great Salt Lake Halophiles
Pigments in _________ in phototrophic bacteria trap light energy for metabolic processes thylakoids
Most cyanobacteria form _________ in which nitrogen fixation occurs heterocysts
what are giant bacteria that are large enough to be seen without a microscope? Selenomonas
the type of reproduction in prokaryotes that results in a palisade arrangement of cells is called? snapping division
the thick walled reproductive spores produced in the middle of cyanobacterial filaments is called? terminal endospores
what best describes stiff, spiral-shaped prokaryotic cells? spirilla
what can remain alive for decades, remain alive in boiling water, exist in a state of suspended animation? endopores
how is halobacterium distinctive? it is absolutely dependent on high salt concentrations to maintain its cell wall
photosynthetic bacteria that also fix nitrogen are ___________ cyanobacteria
what genus is the most common anaerobic human pathogen? bacteroides
flexible spiral shaped prokaryotes are ______ spirochetes
bacteria that convert nitrogen gas into ammonia are __________ nitrogen fixers
the presence of mycolic acid in the cell wall characterizes what? mycobacterium
3 eukaryotic microorganisms protozoa, algae, fungi
single copy (haploid) occurs through what process? meiosis
what reproduces mostly through meiosis fungi
2 copy (diploid) occurs through what process? mitosis
what reproduces through mitosis? algae, protozoa
cell partitions that replicate DNA equally between 2 nuclei, exact copies of parent nucleus, remain diploid mitosis
4 phases of mitosis prophase, metaphase, anaphase, telophase
occurs before mitosis begins, DNA & organelles are duplicated interphase
Dna condenses, nucleus dissolves, mitotic spindle moves to poles prophase
DNA lines up in the middle of the cell, mitotic spindle attaches metaphase
DNA pairs split, move towards poles Anaphase (mitosis)
nucleus reforms, organelles and DNA cluster in poles, cleavage furrow forms telophase (mitosis)
nuclear division that partitions parent cells into 4 haploid cells, 2 stages-meiosis I and meisis II-each stage includes 4 stages PMAT Meiosis
homologous chromosomes pair to form tetrads prophase I
tetrads align in the middle of the cell, mitotic spindle attaches metaphase I
chromosomes split, move towards poles Anaphase (meiosis)
nucleus reforms, chromosomes cluster in poles, cleavage furrow forms telophase (meiosis)
DNA not replicated, one chromosome in each cell, mitotic spindle moves toward poles prophase II
chromosomes aligns in the middle of the cell, mitotic spindle attaches metaphase II
division of a cells cytoplasm Cytokinesis
3 characteristics of protozoa? eukaryotic, unicellular, lack a cell wall
most protozoa are _______ chemoheterotrophic
what is the motile feeding stage in protozoa called? trophozoite
what is the resting stage in protozoa called? cyst
fungi cell walls are typically composed of _____ chitin
chemoheterotrophic, do not perform photosynthesis, related to animals, produce antibiotics, decomposer fungi
divided into cells by internal cross walls in fungi septate hypha
no septate partitioned in fungi aseptate hypha
all have some means of asexual reproduction, most also reproduce sexually fungi
some yeasts produce long filaments called _______ psuedohypha
fungal mating types designated as "+" and "-_ sexual spore formation
classifications of fungi zygomycota, ascomycota, basidiomycota, deuteromycetes
recieves nutrition from dead matter saprobes
what fungal classification is saprobes classified under? zygomycota
most human pathogens, food spoilage, beneficial fungi includes penicillium ascomycota
what are beneficial fungi? penicillium, saccharomyces
what category are the fungi: penicillium, saccharomyces classified under? ascomycota
the yeast responsible for making bread, beer & wine saccharomyces
what fungal classification is mushrooms under? basidiomycota
partnership between fungi & photosynthetic microbes, fungus provides nutrients, water, & protection and photosynthetic microbes provide carbohydrates & oxygen lichens
simple, eukaryotic phototrophs, carry out oxygenic photosynthesis using chlorophyll, aquatic algae
classifications of algae green, red & golden algae
share numerous characteristics with plants, green algae chlorophyta
marine, red algae rhodophyta
component of marine phytoplankton, major source of world's oxygen chrysophyta
_________ are animals that carry pathogens arthropod vectors
2 types of arthropod vectors mechanical & biological
what kind of arthropod vector carry pathogens? mechanical vectors
what kind of arthropod vector carry/ host pathogens, transmit disease through bites biological vectors
what 2 classes of arthropods do disease vectors belong to? arachnida & insecta
examples of arachnida ticks, mites
Examples of insecta fleas, flies, mosquitos
haploid nuclei contain how many sets of chromosomes? 1
multiple nuclear divisions without cytoplasmic divisions result in cells called______ coenocytes
the type of asexual fungal spore that forms within hyphae is called a ________ chlamydospores
what does a phycologist study? alterations of genes in algae
the stemlike portion of a seawood is called its ________ stipe
carrageenan is found in the cell walls of which group of algae? red algae
chrysolaminarin is a storage product found in which group of microbes? golden algae
what feature characterizes diatoms? chlorophylls a and c & carotene
amoebae include microbes with _______ threadlike psuedopods
what is common to mitosis & meiosis? spindle
what taxon is characterized by "hairy" flagella stramenopila
minuscule, acellular, infecious agents, cause infections of humans, animals, plants & bacteria, no cytoplasmic membrane, cytosol, organelles,"non-living" cannot reproduce on its own viruses
virus particles contain genetic material & a ___________ capsid shell
this genetic material filled capsid is called ________ nucleocapsid
provide protection for viral nucleic acid, means of attachment to host's cells capsids
a "phage" virus that only infects bacterial cells bacteriophage
acquired from host cell during viral replication or release, composed of host phospholipid bilayer & proteins, not on all viruses the viral envelope
what are viruses classified by? nucleic acid (RNA/DNA), presence of envelope, shape (helical, cylindrical, icosahedral), size
what is dependent on hosts' organelles and enzymes to produce new virions viral replication
2 types of viral replication lytic & lysogenic
viral replication usually results in death & lysis of host cell lytic replication
5 stages of lytic replication cycle attachment, entry, synthesis, assembly, release
modified replication cycle, infected host cells, grow & reproduce normally for generations before they lyse, usually incorporate viral genetic material into the DNA of the host lysogeny
when the cell is infected with an inactive lysogenic virus, that cell has a ________ latent infection
viruses cause ________% of human cancers 20-25
specific viruses are known to cause ______% of human cancers 15
some carry copies of oncogenes as part of their genomes, some interfere with tumor repression, some promote oncogenes already present in host role of viruses in cancer
3 different mechanisms in which animal viruses enter cells direct penetration, membrane fusion, endocytosis
viruses that enter cell with capsid intact are ______ uncoated
direct penetration is done by? phages only
membrane fushion is done by? enveloped viruses
endocytosis is done by? enveloped and non-enveloped viruses
entry & uncoating is done by? animal viruses
DNA viruses often enter the _______ nucleus
RNA viruses often replicate in the ______ cytoplasm
similar to replication of cellular DNA, viral genome replicated in the nucleus, viral proteins are made in the cytoplasm dsDNA viruses
cells do not use ssDNA, host enzymes produce DNA strand complementary to vital genome to form dsDNA molecule, dsDNA used for viral replication & transcription ssDNA viruses
contains reverse transcriptase that generates DNA from RNA retroviruses +ssRNA
strand of genome acts as mRNA dsRNA viruses
RNA-dependent RNA polymerase generated +ssRNA -ssRNA viruses
enveloped viruses are often released by ________ budding
naked viruses are released by _________ exocytosis or lyse
________cannot grow in standard microbial media viruses
how are viruses cultured? media consisting of mature organisms, embryonated eggs, cell cultures
how are phages grown? in bacteria, in liquid cultures or on agar plates
lysis of bacteria produces ______ plaques
pros of culturing viruses in embryonated chicken eggs? inexpensive, sterile, some vaccines are prepared in chicken cultures
what virus is common culture in chicken eggs? the influenza vaccine
very small, circular pieces of RNA that are infectious & pathogenic in plants, lack capsid, not pathogenic in humans viroids
proteinaceous infectious agent prion
most famous prion disease? variant Creuztfeldt-jakob disease (vCJD) "Mad Cow disease"
functional proteins that contain α-helics cellular PrP
disease causing proteins, contain β-pleated sheets prion PrP
________ causes cellular PrP to refold into prion PrP, normal proteins become non-functional Prion PrP
what disease does the poxviridae virus cause? orthopoxvirus (smallpox)
what diseases does the herpesviridae virus cause? herpes, chicken pox, mono, birth defects
what disease does the papillomaviridae virus cause? human papilloma virus
what disease does the picornaviridae virus cause? polio, hepitis B, common cold
what disease does the coronaviridae virus cause? coronavirus (common cold)
what disease does the retroviridae virus cause? AIDS
What disease does the orthomyxoviridae virus cause? influenza virus (Flu)
what disease does the filoviridae viruse cause? filovirus (ebola)
a naked cell has no ______ membranous envelope
when a eukaryotic cell is infected with an enveloped virus and sheds viruses slowly over time, this infection is called a_________ persistent infection
another name for a complete virus is ________ virion
what virus can be latent? herpesviruses
a clear zone of phage infection in a becterial lawn is called a ________ plaque
Created by: valerie6195