MMG 1650 exam 1

microbiology

literal: study of small living things study of microbes (often invisible to naked eye)

microbe

cellular, living microorganisms such as bacteria, archaea, fungi, protists, and helminths and nonliving/noncellular entities such as viruses and prions

microorganism

cellular, living microorganisms such as bacteria, archaea, fungi, protists, and helminths

Koch's Postulates

1. The same organism must be present in every case of the disease but not present in healthy individuals

2. The organism must be isolated from the diseased host and grown as a pure culture

3. The isolated organism should cause the disease in question when it is inoculated into a susceptible host

4. The organism must then be reisolated from the inoculated, diseased animal

prokaryote/prokaryotic

unicellular, lack a nucleus bacteria and archaea

eukaryote/eukaryotic

multicellular or unicellular, distinct nucleus animal, plant, fungal, protists

taxonomy

branch of science concerned with classification, especially of organisms domain, kingdom, phylum, class, order, family, genus, species

kingdom

below domain (6) animalia, plantae, fungi, protista, archaea, bacteria

binomial nomenclature

2 name system including genus and species designations

genus

A group of similar species (first name, capitalized)

species

group of organisms on the basis of genetic similarity, biochemical, and phenotypic criteria (second name, lowercase)

bacteriology

study of bacteria

mycology

study of yeasts and molds

mycoses

disease caused by fungi

parasitology

study of protozoa and helminths (& ectoparasites)

ectoparasite

a parasite that lives on the outside of its host

helminth

parasitic worm

protozoa

animal like protists that are unicellular, lack a true cell wall, exhibit asexual and sexual reproduction, and typically live by heterotrophic means

virology

study of viruses

infectious disease

illness caused by a pathogen

etiological agent

causative agent

true pathogen

does not require a weakened host to cause disease

opportunistic pathogen

only cause disease when their host is weakened in some way

strain

genetic variants of the same species OR descendants of a species that are classified based on unique characteristics defined by serotyping, enzyme typing, protein/nucleic acid plasmic characterization

binary fission

asexual form of reproduction used most by prokaryotic cells

1. cell copies its DNA containing chromosome

2. cell elongates

3. septum starts to form

4. cell is partitioned

5. daughter cells separate

generation time

the time it takes for a population to double

growth/culture media

mixtures of nutrients that support organismal growth in an artificial setting can be solid, liquid, or semisolid

colony

grouping of cells that developed from a single parent cell

polymicrobial

more than one species

biofilm

sticky communities made up of single or diverse microbial species planktonic (free floating) bacteria adhere to a surface

bacillus

rod or cylindrical shape

coccus

spherical

vibrio

comma shaped

coccobacillus

ovoid (oval)

spirochete

spiral shaped

diplococcus

paired cocci

peptidoglycan

protein carbohydrate substance, component of bacterial cell walls

lipopolysaccharide (LPS)

glycolipid that enriches the outer membrane of gram negative bacteria

gram stain

classifies bacteria as gram positive or gram negative based on differences in cell wall structure positive: purple, thick layer of peptidoglycan (no outer membrane) negative: pink, thin layer of peptidoglycan (one outer membrane)

cell wall

lies just outside plasma membrane, all contain peptidoglycan, provides structure and protection

acid-fast

have waxy cell walls with mycolic acid, bright pink/red

capsule

sticky carbohydrate based structures that some bacteria produce as a form of protection/adherence

flagella

tail like structures used for motility

fimbriae

short, bristle like structures that extrude from the cell surface, adhesive

pili

longer, more rigid, less numerous than fimbriae, used to adhere to surfaces, move, and aid in gene transfer through conjugation

nucleoid

contains prokaryotic DNA, RNA, some proteins, centralized region of the cell, not membrane enclosed

ribosomes

organelle made of RNA and protein, nonmembrane bound, build proteins by linking RNA

endospore

specialized dormant structures made in response to stressful/harsh conditions

endocytosis

Importation of matter by a eukaryotic cell by invagination of its membrane to form a vacuole

1. pinocytosis

2. phagocytosis

3. receptor mediated endocytosis

exocytosis

Exportation of matter that involves vesicles delivering their contents to the plasma membrane

phagocytosis

endocytosis of large particles ("cell eating")

phagosome

Endocytic vesicle formed by phagocytosis

lysosome

vesicle like organelle packed with hydrolytic enzymes

phagolysosome

Intracellular vesicle formed by fusion of a phagosome with a lysosome, in which the phagocytosed material is broken down by degradative lysosomal enzymes.

endosome

small vesicle with an acidic interior

yeast

unicellular fungi, may form chains of cells, smooth/creamy, look similar to bacterial colonies

mold

multicellular fungi, "fluffy" colonies, requires special stains to visualize

hyphae

collection of tubular structures by which fungi grow

mycelium

densely branched network of the hyphae of a fungus

dimorphic fungi

grow as yeast or mold depending on conditions (two forms)

spores/conidia

reproductive unit of a fungus (critical to identifying fungal species)

Psuedohyphae

result of a sort of incomplete budding where the cells elongate but remain attached after division

virion

single, infectious virus particle

1. Genetic material (DNA or RNA) 2)capsid (protein shell)

2. OPTIONAL envelope (membrane surrounding capsid)

naked virus

virus without an envelope

enveloped virus

virus with a lipid based coating that surrounds the capsid (envelope)

lysis

host cell bursts and virions spill out; common with naked viruses

budding

virions bud off host cycle membrane; common with enveloped viruses

host range

the collection of species that a pathogen can infect

tropism

preference of a pathogen for a specific host (or even a specific type of cell within the host)

pathogen

microbes that cause disease

medical microbiology

branch of medical science concerned with the prevention, diagnosis and treatment of infectious diseases

prodromal phase

patient starts to feel rundown and may have mild symptoms

acute phase

experience full blown classical symptoms of the disease

convalescent phase

not fully better but recovering; involves elimination of pathogen from body

sign

objective indicators of disease that can be measured or verified ex: fever, rash, blood in stool

symptom

sensed by the patient and are subjective rather than precisely measurable ex: pain, fatigue, nausea

asymptomatic

no signs/symptoms of infection

epidemiology

studies patterns in disease incidence and control and prevention literal: what is upon the people

morbidity

existence of disease

mortality

number of deaths during specific time period

endemic

routinely detected in a population/region ex: common cold/flu

epidemic

widespread disease outbreak in particular region during a specific time frame

pandemic

worldwide outbreak of disease

reservoir

animate or inanimate habitat where the pathogen is naturally found

vector borne transmission

spread of disease via organism (arthropods & rodents) that spread infectious agents to susceptible hosts

biological vector

organism has role in the pathogens life cycle

mechanical vector

spreads disease without being integral to pathogen life cycle

food borne transmission

food contaminated with feces from an infected animal

vertical transmission

pathogen passes from mother to offspring during pregnancy, delivery, or via breast milk

endogenous

pathogen came from hosts own body ex: misplaced normal microbiota, disrupted microbiota and opportunistic pathogens

exogenous

source external to host ex: animals, humans, environmental

portal of entry

any site that a pathogen uses to enter the host ex: eye, ear, respiratory, skin, GI tract

parenteral entry

entry though skin (bites, cuts, injections, and surgical incisions)

portal of exit

any route a pathogen uses to exit the host ex: feces, urine, bodily fluids, respiratory droplets

communicable disease

transmits from human to human

zoonotic disease

spread from animals to humans

Healthcare acquired infection (HAI)

an infection that a patient develops while receiving care in a healthcare setting

nosocomial infection

synonym for HAI

mutualism

helps host

commensalism

no perceived benefit or cost to host