Finals Definition Flashcards
chapters: 11, 12, 13, 14, 15, and 20 (169 cards)
1
Q
Bacteria with a thin peptidoglycan layer and an outer membrane containing lipopolysaccharides; this structure protects them from phagocytosis, antibiotics, and includes the endotoxin Lipid A.
A
Gram-negative bacteria
2
Q
The largest phylum of bacteria, highly diverse, includes five classes (Alpha, Beta, Gamma, Delta, Epsilon); named after “Proteus” due to their shape-shifting nature.
A
Proteobacteria
3
Q
Obligate intracellular parasites that live inside blood vessel cells, transmitted by ticks, and cause diseases like Rocky Mountain Spotted Fever
A
Rickettsia
4
Q
Nitrogen-fixing bacteria that live in legume root nodules and form a mutualistic relationship with the plant by providing usable nitrogen in exchange for nutrients.
A
Rhizobium
5
Q
The process of converting nitrogen gas (N₂) into ammonia (NH₄⁺), making nitrogen usable by organisms.
A
Nitrogen fixation
6
Q
A free-living, chemoautotrophic bacteria that converts nitrite (NO₂⁻) into nitrate (NO₃⁻), a usable nitrogen form for plants; involved in nitrification.
A
Nitrobacter
7
Q
The biological conversion of ammonia (NH₄⁺) into nitrate (NO₃⁻), typically by bacteria like Nitrosomonas and Nitrobacter.
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Nitrification
8
Q
A chemoautotrophic sulfur-oxidizing bacteria that converts hydrogen sulfide (H₂S) into sulfate (SO₄²⁻); uses inorganic compounds for energy and CO₂ as a carbon source.
A
Thiobacillus
9
Q
Chemoheterotrophic cocci bacteria that attach to host cells via fimbriae; includes species like N. gonorrhoeae (gonorrhea) and N. meningitidis (meningitis).
A
Neisseria
10
Q
Metabolically diverse bacteria with large genomes; capable of growing on unusual substances (like soap), resistant to antibiotics, and involved in denitrification.
A
Pseudomonas
11
Q
The conversion of nitrate (NO₃⁻) into nitrogen gas (N₂) by bacteria like Pseudomonas, returning nitrogen to the atmosphere in an unusable form.
A
Denitrification
12
Q
An order of facultative anaerobic, rod-shaped bacteria that inhabit mammal intestines, ferment carbohydrates, and have structures like fimbriae, pili, and flagella.
A
Enterobacteriales
13
Q
A common gut bacterium in humans; generally harmless but can cause UTIs and traveler’s diarrhea.
A
Escherichia
14
Q
A pathogenic bacteria typically found in the chicken GI tract; not part of normal human microbiota.
A
Salmonella
15
Q
Bacteria that produce a red pigment and are often associated with nosocomial (hospital-acquired) infections
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Serratia
16
Q
Bacteria responsible for the plague, naturally found in the GI tract of rodents.
A
Yersenia
17
Q
Photosynthesis that produces oxygen by oxidizing water (H₂O → O₂).
A
Oxygenic photosynthesis
18
Q
Oxygenic photosynthetic bacteria that use light to make energy and fix nitrogen in specialized cells called heterocysts.
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Cyanobacteria
19
Q
Photosynthesis that does not produce oxygen, often using H₂S or H₂ instead of water.
A
Anoxygenic photosynthesis
20
Q
Photoautotrophic bacteria that perform anoxygenic photosynthesis using sulfur compounds.
A
Green sulfur bacteria
21
Q
Photoautotrophic, anoxygenic photosynthetic bacteria that use sulfur as an electron donor.
A
Purple Sulfur bacteria
22
Q
Photoheterotrophic bacteria that perform anoxygenic photosynthesis using hydrogen instead of sulfur.
A
Green non-sulfur bacteria
23
Q
Photoheterotrophic, anoxygenic photosynthetic bacteria that use organic compounds instead of sulfur.
A
Purple non-sulfur bacteria
24
Q
Obligate intracellular parasites that infect mucosal cells; cause STIs and blindness.
A
Chlamydia
25
Helical-shaped, motile bacteria with axial filaments; include Treponema and Borrelia.
Spirochetes
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Bacteria with a thick peptidoglycan cell wall and no outer membrane.
Gram-positive bacteria
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A group of Gram-positive bacteria with low G+C content, many of which form endospores.
Firmicutes
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A dormant, highly resistant structure formed by some bacteria to survive harsh conditions.
Endospores
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Anaerobic, endospore-forming rods; includes species causing tetanus, botulism, and C. difficile infection.
Clostridium
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Rod-shaped, endospore-forming, facultative anaerobes; some species produce antibiotics.
Bacillus
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Coccus-shaped bacteria in grape-like clusters; includes S. aureus, often antibiotic-resistant.
Staphylococcus
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Rod-shaped, aerotolerant anaerobes that use lactic acid fermentation; found in normal flora and fermented foods.
Lactobacillus
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Chain-forming cocci, aerotolerant anaerobes; cause diseases like strep throat and pneumonia.
Streptococcus
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Gram-positive bacteria with high G+C content, often filamentous and soil-dwelling.
Actinobacteria
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Rod-shaped, acid-fast bacteria with mycolic acids; includes M. tuberculosis and M. leprae
Mycobacteria
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Filamentous soil bacteria that produce conidiospores and are the source of many antibiotics.
Streptomyces
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Archaea that require high salt concentrations (>25%) to survive.
Halophiles
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Archaea that grow best at extremely high temperatures (>80°C).
Extreme thermophiles
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Archaea that produce methane; found in anaerobic environments like swamps and animal guts
Methanogens
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The thallus (body) of multicellular fungi, like mold or mushrooms, composed of filaments called hyphae.
Mycelium
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Long filamentous cells that form the mycelium of multicellular fungi.
Hyphae
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Fungi that exhibit variable growth forms, as either yeast at 37°C or mold at 25°C.
Dimorphic fungi
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Unicellular fungi
Yeast
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Multicellular fungi
Mold
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A reproductive structure of fungi that develops into a new organism, produced by aerial hyphae and used for organism dispersal.
spore
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A phylum of fungi including molds with coenocytic hyphae, producing asexual sporangiospores and sexual zygospores.
Zygomycota
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A genus of Zygomycota that can cause respiratory infections.
Rhizopus
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A phylum of fungi including molds with septate hyphae, producing asexual conidia and sexual ascospores
Ascomycota
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A genus of Ascomycota that can cause urinary infections.
Candida
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A phylum of fungi including mushrooms with septate hyphae, reproducing asexually via vegetative propagation and sexually via basidiospores.
Basidiomycota
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A genus of Basidiomycota that can cause meningitis.
Cryptococcus
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Multicellular, macroscopic algae that provide ecological habitats like kelp forests and have no known pathogens.
Brown algae
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Multicellular algae that live at the deepest ocean depths, possess a branched thallus, are harvested for agar, and can produce lethal toxins.
Red algae
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Unicellular, non-motile algae with complex cell walls containing silica and pectin, and produce neurotoxins transmitted via shellfish.
Diatom
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Unicellular, motile algae with cell walls composed of cellulose, and produce neurotoxins transmitted via shellfish.
Dinoflagellate
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A symbiotic organism consisting of a combination of fungi and algae (green), in a mutualistic relationship where fungi provide physical protection and algae provide nutrients (carbohydrates).
Lichen
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A form of asexual reproduction in protozoa involving multiple fission.
Schizogony
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The vegetative (metabolic) form of a protozoan.
Trophozoite
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The dormant (non-vegetative) form of a protozoan, produced during adverse conditions and featuring a protective capsule.
Cyst
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A genus of protozoa that lacks mitochondria, has two nuclei, and is motile via flagella. Giardia intestinalis inhabits the small intestine of mammals and can cause giardiasis, with cysts transmitted via water.
Giardia
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Protozoa that are motile via pseudopods (plasma membrane extensions) and feed via phagocytosis. Entamoeba inhabits intestines and can cause amoebic dysentery.
Amoeba
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A genus of non-motile protozoa transmitted via insect vectors, obligate intracellular parasites with a complex life cycle. Plasmodium inhabits red blood cells and causes malaria.
Plasmodium
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The host that harbors the sexual reproduction phase of a parasite. For example, the mosquito is the definitive host for malaria.
Definitive host
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A parasitic worm
Helminth
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Having reproductive organs on different organisms, involving opposite sexes where the female egg is fertilized.
Dioecious
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Having reproductive organs on the same organism, involving hermaphrodites with simultaneous egg fertilization.
Monoecious
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A class of Platyhelminthes (flatworms) also known as flukes, with flat leaf-like bodies and attachment via oral/ventral suckers. They have an incomplete digestive system and are monoecious.
Trematode
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A genus of trematode known as the lung fluke. The definitive host is mammals, inhabiting the respiratory tract and transmitted via crustaceans. Infective form is cysts.
Paragonimus
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A class of Platyhelminthes (flatworms) also known as tapeworms, with flat ribbon-like bodies and attachment via a scolex. They are composed of many proglottids (reproductive units) and lack a digestive system. Monoecious.
Cestode
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The head region of a tapeworm, used for attachment, with suckers/hooks.
Scolex
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Reproductive units that make up the body of cestodes (tapeworms).
Proglottids
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A genus of cestode (tapeworm). The definitive host is humans, inhabiting the digestive tract and transmitted via beef/pork. Infective form is cysts.
Tenia
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A phylum of helminths also known as roundworms, with cylindrical tapered bodies and a complete digestive system (mouth to anus). Most common infectious disease, dioecious (females larger than males).
Nematode
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Roundworms that have humans as their definitive host, inhabit the digestive tract, and are transmitted through infective eggs.
Ascaris
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An external protein coat. It is composed of capsomeres and its function is protection.
Capsid
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A complete viral particle (nucleic acid + capsid).
Virion
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An external structure surrounding the capsid, composed of host-derived lipids and proteins, that functions in immune system evasion.
Envelope
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Projections from the surface of the envelope, which are carbohydrate-protein complexes and function in host cell attachment.
Spikes
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Binding to host cell membrane via receptor sites with complementary host/virus proteins (e.g., spikes).
Attachment
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Penetration into host cell.
Entry
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Host plasma membrane surrounds virion, and vesicle enters host cytoplasm.
Receptor-mediated endocytosis
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Envelope fuses with host plasma membrane, and capsid is released into host cytoplasm
Fusion
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Release of nucleic acids from capsid into host cell, typically via host cell enzymes (lysosomes, phagosomes)
Uncoating
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Production of virion components (nucleic acids and proteins). Major variations include DNA viruses, RNA viruses, and retroviruses.
Biosynthesis
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A non-enveloped, double-stranded DNA virus (e.g., common cold).
Mastadenovirus
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Virus with DNA in its virion. Nucleic acid synthesis occurs in the nucleus using host polymerase, and protein synthesis occurs in the cytoplasm using host ribosomes.
DNA virus
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An enveloped, double-stranded DNA virus (e.g., smallpox).
Orthopoxvirus
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An enveloped, double-stranded DNA virus (e.g., cold sores/herpes).
Simplexvirus
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Virus with RNA in its virion. Nucleic acid synthesis occurs in the cytoplasm using viral polymerase, and protein synthesis occurs in the cytoplasm using host ribosomes.
RNA virus
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Viral enzyme used for nucleic acid synthesis in RNA viruses.
RNA polymerase
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A non-enveloped, single-stranded RNA (+ strand) virus (e.g., common cold)
Rhinovirus
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Viral enzyme in retroviruses used to produce DNA from viral RNA.
Reverse transcriptase
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An enveloped, single-stranded RNA (+ strand) virus (hepatitis C).
Hepatitis C virus
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An enveloped virus with multiple, single-stranded RNA (- strand) segments (e.g., flu).
Influenzavirus
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Virus with RNA in its virion that uses reverse transcriptase. Viral DNA is integrated into host DNA, and protein synthesis occurs in the cytoplasm using host ribosomes.
Retrovirus
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An enveloped, single-stranded RNA virus (e.g., HIV).
Lentivirus
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Assembly of virion components.
Maturation
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Development of disease.
Pathogenesis
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Exiting host cell.
Release
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Release process where the host plasma membrane surrounds the virus, forming an envelope.
Budding
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Release process where the host cell lyses (typically kills the host cell).
Rupture
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Study of disease; Impairment of normal body functions.
Pathology
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Functional changes associated with disease
Pathophysiology
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Cause of disease; Study of disease cause; Identifies specific disease agent.
Etiology
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Impairment of normal body functions.
Disease
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Invasion of body by pathogens
Infection
100
Disease causing microbe.
Pathogen
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Temporarily colonize host (days – months); Do not typically cause disease.
Transitional Microbiota
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Permanently colonize host; Do not typically cause disease.
Normal Microbiota
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Competition between microbes; Benefit the host; Prevents overgrowth of pathogens.
Competitive exclusion
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Relationship between two organisms; One organism is dependent on other.
Symbiosis
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One organism benefits; One organism unaffected.
Commensalism
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One organism benefits; One organism harmed.
Parasitism
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Both organisms benefit.
Mutualism
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Continual source of infection.
Reservoir
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Framework for infectious disease etiology; Provides strong correlation between Disease and Pathogen.
Koch’s postulates
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Direct spread of infection; No living or non-living vehicle.
Contact Transmission
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Does not typically cause disease; Able to cause disease is certain situations.
Opportunistic Pathogen
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Movement of infection; Between reservoir and host.
Transmission
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Indirect spread of infection; Movement via non-living medium.
Vehicle Transmission
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Indirect spread of infection; Movement via living medium.
Vector Transmission
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Pathogen carried on insect body.
Mechanical Transmission
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Pathogen reproduces within insect.
Biological Transmission
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Factors affecting host susceptibility: Age, Gender, Environment, Health.
Predisposing Factors
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New individuals contracting disease
Incidence
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Latent Disease
Very long incubation period
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Very long incubation period.
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Develops rapidly / lasts for short-time.
Acute Disease
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Total population possessing disease.
Prevalence
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Develops slowly / last for long-time.
Chronic Disease
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Disease occurs occasionally
Sporadic
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Degree of pathogenicity.
Virulence
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Constantly present in population.
Endemic
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Pathogen must enter host.
Portal of entry
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Many regional diseases in short-time.
Epidemic
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Many world-wide diseases in short-time.
Pandemic
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Ability to cause disease.
Pathogenicity
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External body surface.
Skin (Integument)
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Internal body surface.
Mucous membrane
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Free-floating protein molecule; Produced by host immune cells; Inhibit pathogen functions; Binds pathogen antigens.
Antibody
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Damaged body surface.
Parenteral route
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Virulence threshold for specific microbe; Number of organisms required for disease.
nfectious Dose Size (ID50)
120
Cell-surface protein molecules; Located on pathogen cells; Activate host immune cell → release antibodies.
Antigen
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Harmful substance; Produced by microorganisms.
Toxin
122
Presence of toxin; Does not require microbial growth.
Intoxication
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Inactivated toxin (vaccine); Does not cause disease; Stimulates antitoxin production.
Toxoid
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Defense molecule produced by host (antibody); Produced after exposure to toxin.
Antitoxin
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Component of bacteria cell; Remains inside of cell; Released after cell destruction.
Endotoxin
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Contain 2 subunits; A unit - Active component (enzyme) Alters host cell function Often inhibits protein synthesis; B unit - Binding component Attaches to host cell Facilitates host cell entry.
A-B toxin
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Molecule synthesized by bacteria; Released outside of cell; Released during normal cell function.
Exotoxin
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A toxin that causes lysis of host cells by damaging the cell membrane through mechanisms such as protein channel formation or phospholipid disruption; leukocidins are a type of membrane-disrupting toxin that kill phagocytic immune cells (white blood cells).
Membrane-disrupting toxin
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Toxins that cause an extreme immune reaction in the host, characterized by the excessive release of cytokines (immune stimulating chemicals); this reaction is triggered by antigen recognition and can lead to symptoms such as fever, inflammation, vomiting, diarrhea, shock, and potentially death.
Superantigens
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A substance that inhibits microbial growth within the host. These drugs can either kill microbes (biocidal) or prevent their growth (biostatic), and include both natural and synthetic compounds. Antimicrobial drugs target certain essential functions of the microbe.
Antimicrobial drug
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A substance produced by microorganisms that inhibits the growth of or kills other microbes. Antibiotics can be either biocidal or biostatic.
Antibiotic
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Refers to substances or actions that directly kill microbes.
Biocidal
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Refers to substances or actions that inhibit the growth and reproduction of microbes without directly killing them.
Biostatic
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The ability of an antimicrobial drug to inhibit or kill microbes without causing harm to the host organism.
Selective toxicity
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An antibiotic that affects a wide range of microbial species, including both gram-positive and gram-negative bacteria. Useful for treating unknown infections, but may disrupt normal microbiota and lead to superinfections.
Broad-spectrum antibiotic
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An antibiotic that targets a specific group of microbes, often only gram-positive or gram-negative bacteria. It minimizes disruption to the normal microbiota.
Narrow-spectrum antibiotic
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A narrow-spectrum antibiotic that inhibits cell wall synthesis by targeting peptidoglycan cross-linking. It contains a β-lactam ring and is primarily effective against gram-positive bacteria
Penicillin
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A β-lactam antibiotic that inhibits cell wall synthesis.
Cephalosporin
136
A broad-spectrum antibiotic that inhibits protein synthesis by blocking tRNA attachment to the ribosome. Effective against a wide range of bacteria, including chlamydia and rickettsia.
Tetracycline
136
A broad-spectrum antibiotic that inhibits protein synthesis.
Streptomycin
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A narrow-spectrum antibiotic that inhibits protein synthesis by binding to the 50S ribosomal subunit. Primarily targets gram-positive bacteria.
Erythromycin
138
A bactericidal antibiotic that disrupts the plasma membrane, leading to increased permeability and cell lysis. Effective against gram-negative bacteria, especially Pseudomonas. Often used topically.
Polymyxin B
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A broad-spectrum antibiotic that inhibits DNA replication. It is biostatic.
Fluoroquinolone
139
A broad-spectrum antibiotic that inhibits folic acid synthesis, indirectly preventing DNA and RNA production. It is biostatic.
Sulfamethoxazole
139
The ability of microbes to survive exposure to an antibiotic that would normally kill or inhibit them. Resistance arises due to genetic mutations or horizontal gene transfer and can involve mechanisms such as blocking drug entry, inactivating the drug, pumping the drug out (efflux), or altering the drug's target.
Antibiotic resistance
