MICR J210: EXAM 1
89 Cards in this Set
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Antoni van Leeuwenhoek (1632–1723)
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made the first simple microscope-He reported the existence of protozoa in 1674 and of bacteria in 1676.
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Carolus Linnaeus (1707–1778)
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developed a taxonomic system for naming plants and animals and grouping similar organisms together
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Eukaryote
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any organism made up of cells containing a nucleus composed of genetic material surrounded by a distinct membrane.
*2 copies of each chromosome
*Membrane bound organelles
Ex: animals, plants, algae, fungi, and protozoa.
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Prokaryotes
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-unicellular organisms
-lack a nucleus
-no membrane bound organelles
-bacteria and cynobacteria
-One copy of chromosome
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Fungi
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are relatively large microscopic eukaryotes and include molds and yeasts. These organisms obtain their food from other organisms and have cell walls
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Protozoa
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are single-celled eukaryotes that are similar to animals in their nutritional needs and cellular structure. Most are capable of locomotion, and some cause disease
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Algae
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are plantlike eukaryotes that are photosynthetic; that is, they make their own food from carbon dioxide and water using energy from sunlight
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Bacteria
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are unicellular prokaryotes whose cell walls are composed of peptidoglycan (though some bacteria lack cell walls). Most are beneficial, but some cause disease
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Archaea
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are single-celled prokaryotes whose cell walls lack peptidoglycan and instead are composed of other polymers.
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Viruses
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are microbes so small that they were hidden from microbiologists until the invention of the electron microscope in 1932. All are acellular obligatory parasites.
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Parasitic worms
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range in size from microscopic forms to adult tapeworms several meters in length
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spontaneous generation
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proposes that living organisms can arise from nonliving matter. It was proposed by Aristotle (384–322 b.c.) and was widely accepted for almost 2000 years, until experiments by Francesco Redi (1626–1697) challenged it.
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Francesco Redi
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1626-1697
exp disproves theory of spontaneous generation
spontaneous gen: living organisms arose from nonliving matter
meat exp
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Pasteur
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Experiments with long necked flasks and causes of fermentation. Also developed germ theory of disease
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Ignaz Semmelweiss
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Initially concerned about high mortality rates in maternity wards. Discovered doctors were not washing hands between autopsies and delivering babies. Advocated hand washing!
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Robert Koch
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-found principles to prove an organism causes disease
1. Microbe present in sick and absent in healthy
2. Microbe purified and grown in pure culture (only organism growing in it, cant do with viruses)
3. Inoculate healthy host with microbe and host must be come sick
4. From sick must …
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Transmission electron microscope
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Greatest magnifications up to 1 million times. Can not see color only density
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Scanning electron microscope
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Electrons bounce off surface of specimen. Only surface features visible (almost 3D image of cell)
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Prokaryote flagellum
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Motion is rotational
Embedded in cell envelope
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Eukaryote Flagellum
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Flagella are internal, entirely surrounded by cytoplasmic membrane
Only found on one pole of cell
Action is rhythmic undulation which pushes or pulls the cell
Do not pierce the cell membrane
Composed of microtubules
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Chemotaxis
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Movement in response to a chemical present in the environment.
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Phototaxis
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movement of an organism toward light
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Cilia
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Short hair like structures only found in Eukaryotic cells
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Pseudopoda
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How WBCs move. WBCs are motile but they crawl by using microfilaments and microtubules forming pseudopods
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Ribosomes in Euk and Prok cells
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Euk ribosomes are larger and heavier. We can make medicines that specifically target Prok ribosomes and not harm Euk
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Bacillus
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Rod shaped (almost pill shaped) bacteria
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Coccus
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sphere, ball, round bacteria
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streptococci
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bacteria in twisted chains
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Diplococci
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pairs of spherical cells
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staphylococci
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Round bacteria that is clustered together
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Cytosol
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Liquid found inside cells - in Prok cells most chemical reactions of metabolism take place here
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Pili (Fimbriae)
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Type 1 - used to attach to target tissues
Type 2 - sex pilus present only in GRAM NEGATIVE BACTERIA FOR GENETIC EXCHANGE
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Gram Positive Cells
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Single membrane
Thick peptidoglycan layer
Stain Blue/purple
Sensitive to penicillin
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Gram Negative Cells
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Thin layer of peptidoglycan
2 membranes
Lipopolysaccharide on outer membrane surface
Stains Pink/Red
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Lipopolysacchardie
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Also called endotoxin
Released when bacteria destroyed, moves into blood stream
Causes septic shock - fever, inflammatory response all over body
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Endospore
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Most stable living thing known to man
Survival strategy for Gram Positive bacteria
In response to harsh conditions
Resists drying, freezing, ultraviolet light and time
Once reintroduced into nutrient rich environment endospores germinate and produce original or…
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Binary fission
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Bacteria: Asexual reproduction
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Malaria
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disease caused by a parasitic protozoan that infects red blood cells and is carried by Anopheles mosquitos
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Naked virus
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has no membranous envelope
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Enveloped virus
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A virus enclosed within a phospholipid membrane derived from its host cell.
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Bacteriophage
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A virus that infects and usually destroys bacterial cells
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Bacterial Strain
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a population of bacteria that all descend from one single cell in a clonal fashion
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Serovar
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group of microorganisms classified together based on antigens
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catabolism
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break down of larger molecules into smaller ones
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Anabolism
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The synthesis of larger molecules from smaller molecules, can be accomplished using the energy released from catabolic reactions.
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Autotroph
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Self-feeding
Uses Co2 as carbon source
Non organic sources of energy
Photosynthesis by plants and some bacteria
Mostly not pathogenic
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Heterotroph
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Preformed organics used as carbon source and energy source
Humans and pathogens
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Fastidious Microbes
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Requires extra nutritional supplements to grow
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Aerobic respiration
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Oxygen required
Substrate level and oxidative phosphorylation
Final electron acceptor is oxygen
Potential molecules of ATP produced: 36-38
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Anaerobic Respiration
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No oxygen required
Substrate level and oxidative phosphorylation
Final electron acceptor NO2, So42 or CO3 2-
Potential molecules of ATP produced 2-36
*Each specific type of bacteria only uses one type of electron acceptor
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Fermentation
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No oxygen required
Substrate level phospohorylation
Final electron acceptor organic molecules
Potential molecules of ATP produced 2
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Electron Transport Chain
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A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP. NADH drop off to Complex I & FADH 2 drop off to Complex II Electrons from I & II hop onto CoQ CoQ→ Complex III→CytC→Complex IV→O 2
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Base pairs DNA
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A pairs with T
C pairs with G
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Antibiotic
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Against living organisms
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Antimicrobial
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killing or suppressing growth of microorganisms.
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narrow spectrum
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drug that is effective against a limited range of microbes
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Broad spectrum
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effective in treating a number of different microorganisms
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bactericidal
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antibiotic that kills bacteria
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Bacteriostatic
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Prevent microbes from growing
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Penicillin allergic reaction
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Anaphylaxis which may lead to shock and cause death
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commensals
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microbial population that colonizes the human body and makes up microbial flora
even commensals can become pathogenic, depending on dose, timing, route etc
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Ergosterol
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component of fungal cell membranes; functions like cholesterol (micro)
Often used as a target in antifungal drugs
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Inactivation
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Destroys the drug
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Decreased uptake
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minimize how much antibiotic is taken in
can occur via mutation or acquistion of new genes
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Pump
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Bacteria pumps the drug back out of the cell
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Target overproduction
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In presence of antibiotic, bacteria overproduce enzymes
These outcompete antibiotics
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Metabolic bypass
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Bacteria find a new way to synthesize products
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Griffith's Experiment
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Injected living mice with living non-virulent form of virus and heat-killed virulent form
non-virulent form took on characteristics of virulent form
conclusion: something was causing non-virulent to transform
*Bacteria can exchange genetic information
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Mutation
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a change in the genetic material of a cell
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Spontaneous mutation
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A mutation resulting from abnormalities in biological processes.
- Random.
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induced mutations
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mutations generated to exposure to physical, chemical, or biological mutagens
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Transformation
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Uptake of naked DNA into a cell
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Conjugation
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A form of genetic transfer between bacteria that involves direct physical interaction between two bacterial cells. One bacterium acts as a donor and transfers genetic material to a recipient cell
*The most efficient mechanism of genetic exchange amongst bacteria
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Bacteriophage transduction
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bacterial DNA is transferred from a donor cell to a recipient cell inside a virus that infects bacteria
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Plasmids
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Small circular DNA molecule found in bacteria. A plasmid maybe carry a number of genes and can make copies of itself. Bacteria can share genes by passing a copy of a plasmid from one bacteria cell to another
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R-factors
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Term used for plasmids that carry resistance to antimicrobial agents
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Resident Microbiota
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Microbes that remain part of the normal microbiota of an individual throughout their lfiespan. These organisms are found on the skin, the mucous membranes of the digestive tract, upper respiratory tract, distal portion of the urethra and the vagina. Most are commensal.
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Transient microbiota
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Remain on the body for hours or months before disappearing
Found in the same regions as resident microbiota
Cannot persist in the body
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Opportunisticpathogen
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A microorganism which is usually of low virulence in healthy subjects but is pathogenic in immunocompromised patients
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Symptoms
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Only felt by patient
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Signs
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measurable, observable by clinician
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Syndrome
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set of signs and symptoms associated with a particular disease (example: Down's syndrome).
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asymptomatic
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infection lack symptoms but may still have signs of infection
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Pathogenicity
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the ability of an agent to cause disease.
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Virulence Factors
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Adhesion factors
Biofilms
Extracellular enzymes
Toxins
*Exotoxins- released from bacteria while alive
*Endotoxin- released from bacteria after death
Antiphagocytic factors - bacterial capsule,antiphagocytic chemcials
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5 stages of infectious disease
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1. incubation-time btwn infection and symptoms
2. prodromal period-mild symptoms
3. illness-most severe stage exponential microbe growth
4. decline-signs and symptoms dissapate
5. convalescence-patient recovers
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Reservoirs of infection
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place where pathogens are maintained and serve as source of infection
animal (zoonotic)
human
nonliving
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Zoonoses
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Natural diseases of animals that can be transmitted to humans as accidental hosts.
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Modes of Infectious Disease Transmission
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Contact
Vehicle
Vector
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MICR J210: EXAM 1