micro exam 1 Flashcards
microbiology
- the study of very small living organisms
- usually seen with the aid of the microscope
Living microbes including parasitic are?
1) Bacteria
2) Fungi
3) Algae
4) Protozoa
5) Helminths
Non-Living infectious agents all of which are parasitic/particles
1) Viruses
2) Prion
3) Virods
Saprophytes
-free living bacteria and fungi that live in soil, water, air, an environment from which they derive their nutrients
Decomposition
the process of breaking down dead, organic matter
Parasite
-certain species of bacteria, fungi, protozoa, algae, worms and all viruses live in close symbiotic relationships w. their hosts from which they derive their nutrients. those that cause damage or disease are called parasites.
4 ways microorganisms are beneficial to life(other living matter)
1) Recycle of energy and nutrients in ecosystem
2) Food chain
3) Normal Flora/Resident flora/indigenous flora/microbiota
4) Some microorganisms have commercial and industrial uses
4 ways microorganisms are beneficial to life(Recycle of energy and nutrients in ecosystem)
- photosynthetic algae are beneficial in that they produce glucose(and other org. nutrients)
- release more than 50% of earths 02 in process)
- free living bacteria and fungi(saprophytes) are beneficial in that they release inorganic molecules such as Co2 NO3 back into the environment to be utilized by plants or plant like organisms to make their own food( in various cycles such as carbon or nitrogen cycles)
4 ways microorganisms are beneficial to life(Food chain)
-Photoplankton and zooplankton(aquatic microbes) serve as food for larger animals
4 ways microorganisms are beneficial to life(Normal flora/Resident flora/indigenous flora/Microbiota)
- microbes that adapt to colonize and become permanent residents on the surface of our skin and mucous membranes from which they derive organic nutrients
- they re beneficial in that they break down indigestible sugars in human or other animal intestines, provide us with vitamin(B and K) and prevent the establishment of pathogenic microbes on the surfaces of our skin and mucous membrane,
4 ways microorganisms are beneficial to life(Some microorganisms have commercial and industrial uses)
- Bioremediation: introduction of microbes into the environment to clean up toxic pollutants. eg. oil spills
- Sewage treatments: the use of microbes to recycle(clean) water.
- Biotechnology: manipulation of microbes metabolism to yield desired products, e.g., enzymes, alcohol, cheeses, antibiotics, vaccines
- genetic engineering: newer area of biotechnology that manipulates microbial teens to produce new protein products and genetically modified organisms
genetic engineering techniques are beneficial 3 ways:
- microbial genes can be manipulated to produce drugs such as human insulin, growth hormone or interferon.
- gene therapy to treat certain diseases such as cystic fibrosis
- in agriculture genes from bacteria that are insect resistant can be inserted into plant cells
pathogens
-organisms that cause disease in humans and other organisms
most common infectious diseases that are the common cause of death worldwide
- respiratory
2. diarrheal
emerging disease
- newly identified infectious diseases since 1969
- ex: ebola, hanta pulmonary syndrome, hiv, west nile, avian flu
re-emerging disease
-older infectious diseases that have been known for hundreds of years and recently have been increasing in occurence
Ex. TB. MEASLES. MALARIA
some concerns regarding the spread of infectious disease in developed and underdeveloped countries
- mutations and gene transfer
- immunocompromised patients
- advances in medicine are keeping the aged and sick patients alive longer
- greater mobility
- encroachment of humans into rural or wild habitats
- changes in agricultural practices and deforestaiton
- mass production of foods(meats and vegetables) grown in fecal contaminated soils
- antibiotic drug resistance
non infectious diseases such as heart disease, duodenal ulcers, MS, certain cancers have ben linked w/ microbes
over the past 300 years scientist have contributed to our understanding of the microbial world
Anton Van Leeuwenhoek
1st to observe animalcules (bacteria, protoza, algae) in rainwater, plaque and blood, using his homemade, single-lens microscopes
Francesco Redi
experimentally disproved spontaneous generation by demonstrating that fly maggots todo not arise from decaying meat, but from flies that leave their eggs.
Louis Pasteur
Ended the spontaneous generation vs biogenesis debate by experimentally disproving abiogenesis. He proved that microbes in air enter and contaminate sterile liquids
Joseph Lister
1st to introduce aseptic technique
-use of disinfectant phenol during surgery to prevent wound infections
Robert Koch
Developed a series of experimental steps/proofs(postulates) to verify the germ theory of disease
-ex, bacillus anthracis=anthrax
Edward Jenner
-introduced the first vaccine procedure for smallpox
Paul Erlich
developed the 1st drug(magic bullet), salvias an an arsenic derivative used to treat syphhilis
Alexander Fleming
1st to discover and describe the properties of the drug(2nd magic bullet), penicillin(an antibiotic), produced by mold Penicillium notatum
Rebecca Lancefield
-classified species of streptococci based on antigenic differences in their CW carbohydrates, group A through O
Dimitri Iwanowski
discovered that the tobacco mosaic plant disease as caused by tiny filterable agents called viruses
Spontaneous generation(abiogenesis)
the claim by scientist that certain forms of life arise spontaneously from non-living matter
Biogenesis
belief by scientist that all cells(life) arises from pre-existing cells(living organisms)
Binomial Nomenclature
system of naming organisms that assigns a scientific two-part
genus name
1st name
capitalized(always a noun)
ex. Escherichia(genus) coli(species)
species name
2nd name
- lower case(usually an adjective)
ex. Home(genus) Sapiens(Species)
stain name
numbers or letters to follow the species name
ex: E. coli O157:H7
Taxonomy
branch of biology that deals with the classification, naming, and identification of living organisms
Taxonomic Hierarchy
- 9 groups
- most broad to most specific
- each domain consist of related kingdoms
- each kingdom of related phyla
- each class of related orders
Genus
-organisms that differ in a small number of characteristics but are closely related by evolutionary(phylogenetic descent are categorized in the taxon genus
Species
most specific group that actual organisms where members share most characteristics in common
Strain(population)
-different populations derived from the same species that differ in 1 or 2 characteristics make up a strain
Monera(prokaryote)
simple, small, single celled organisms that lack a nucleus and other membrane bound organelles would be classified in the kingdom monera(prokaryote)
- this kingdom includes free-living and parasitic bacteria.
- an example of a pathogenic/parasitic bacterium is staphyloccous aureus
Protista(Eukaryote)
- large, complex single-celled organisms(eukaryotes) are placed in the kingdom protista
- the two main divisions/phyla in this kingdom are protozoa(before the 1st animal) and microscopic algae.
Protozoa
- single celled animal like organisms
- include free living and parasitic forms
- ex. plasmodium vivax(malaria)
Algae
unicellular, plant like organisms
- inhabit fresh or marine water and cell wall of cellulose
- most are photoautotrophs
- ex: volvox
Fungi
- complex unicellular or multicellular eukaryotic organisms, non-photosynthetic heterotrophs, like animals, but have a cell wall like plants are classified in the kingdom fungi
- cw made of chitin
- macroscopic(mushrooms)
- microscopic(yeast(creamy) and molds(fuzzy)
yeast
- unicellular fungi that form large creamy colonies and reproduce by budding to form pseudohyphae known as yeast
- ex. candida albicans
molds
multicellular fungi that form hyphae(stalks/filaments) interwoven into mats called myceila known as mold
-dimorphic(@ room temp they live as molds, body temp live as yeast.
vegetative hyphae
- outgrowths of spores that penetrate a substrate
- ex. bread
- vegetative hyphae secrete digestive enzymes onto their substrate which break down large organic compounds into simple organic molecules they absorb
ariel/reproductive hyphae
- arise from vegetative hyphae and produce reproductive cells at their tips called spores
- asexual or sexual spores.
- asexual spores reproduce asexually, two types of asexual spores are conidiospores(free) and sporangiospores(in a sac)
plantae
-complex multicellular eukaryotic organisms that are photosynthetic and have a cell wall made of cellulose are in the kingdom plantae
animalia
-complex multicellular eukaryotic organisms that are chemoheterotrophs and do not possess cell walls are animalia
Nemathelminth
- round worms which have rounded bodies pointed at tip
- mouth with hooks
- some are parasitic
Platyhelminth
-flat worms which have flattened bodies
Arthropoda
- have jointed appendages and an exoskeleton made of chitin
- includes insects and spiders
Carl Wise
- proposed that there should be 3 domains based on cell type
- bacteria
- archaea
- eukaryotes
Bacteria(domain)
- small, simple single celled organisms that lack a nucleus and other membrane bound(enclosed) organelles
- have 3 basic shapes(cocci,bacilli,spiral) and rigid walls made of peptidoglycan(pg)
- many possess flagella and reproduce by binary fission
- some species cause disease in humans
Archaea(domain)
-similar to bacteria
-but chemical composition of CW different
-do not cause disease in humans and live i extreme environmental conditions
A. methanogens: produce methane gas from resp process, not o2
B. Extreme Halophiles: live in very salty environment such as the dead sea
C. Extreme Thermophiles: live in hot springs such as in yellow stone national park
Eukaryotes(domain)
- large complex unicellular organisms
- cells have nucleus and other membrane enclosed organelles
- include all other forms of life in kingdoms
- 1.protista(protozoa and algae)
- fungi(yeast and mold)
- plantae
- animalia
3 basic shapes of bacteria
- cocci(round)
- bacilli(ROD)
- Sprial(twisted 1 or times along axis)
sprilla
rigid, helical bodies
spirochetes
flexible, helical bodies
vibrio
curved/comma shaped cells
diplocci
paired cells
tetrad
group of 4 cells
sarcinae
cuboidal packets of 8 cells
streptococci
chains of cells
staphylococci
graph like clusters of cells
streptobacilli
chains of rods
spirochetes and vibrio
- all remain as single cells
- some spirilla form chain
monomorphic
one shape describes most bacteria
pleomorphic
many shapes describes a few bacterial species
-ex, mycoplasma b/c has no cell wall and also smallest bacteria
Structures found in bacterial cells
- flagella
- fimbriae
- sex pili(pilius)
- Glycocolyces
- Cell wall
- Cell membrane/plasma membrane
- cytoplasm
- nucleoid
- ribosomes
- inclusion
- bacterial endosphores
Flagella
- long, fined, thread like appendages/filaments that extend from the surface of the cell, found in all spiral-shaped bacteria, 1/2 of all rod-shaped bacteria and non found in cocci.
- flagella filaments are made of repeating protein molecules called flagellin
Flagella(function)
- motility
- flagella rotate allowing bacteria to swim in aqueous environment
- virulence: flagella attach to mucous membranes of host
4 patterns of arrangement help ID bacteria
- montrichous( 1 flagellum at 1 pole)
- lophotrichous(bunch of flagella at 1 pole)
- Amphitrichous(flagellum at both poles)
- Peritrichous(flagella around entire surface of cell)
Which bacteria exhibit endoflagella(axial filaments)?
SPRIOCHETES ONLY!
Fimbriae
- short appendages that extend over entire surface or poles of the cell
- found in certain pathogenic species
- help form biofilms
- function and virulence: adhesion of bacterial cells to each other or mucous membranes of host
- ex. neisseria gonorrhea
Sex pili(pilus)
- are 1 or 2 rigid tubular structures composed of the protein piling, found in certain species of bacteria
- function: conjugation(mating), a type of genetic/gene transfer
- DNA or plasmid is transferred btw donor F+ and recipent F-bacterial cells
- viruulence: rapidly spread virulent genes between the same or different sp. of bacteria, e.g.. genes of antibiotic resistance
Glycocalyces(sugar coat)
- is a vicious(sticky) gelatinous substance
- made of polysaccharides
- polypeptides or both and secreted by bacterium into CW surfaces
- found usually in pathogenic strains of bacteria
- ex. glycocalyces: capsule(strepococcus pneumoniae
- function and virulence: antiphagocytic and forms antibiotics and salt concentration aldo aid in communication called quorum sensing
cell wall
- complex semi rigid structure exterior to plasma membrane
- fund in all species of bacteria ex. mycoplasma
- function: determines shape of bacteria cells and prevents osmolysis(rupture from too much fluid intake)
gram positive(1 layer)
-one thick layer of PG bound by teichoic acids
gram negative(2 layers)
- thin layer of PG w/ in periplasmic space and outer lipid membrane(a type of phospholipid bilayer)
- the outer membrane contains lipopolysaccharides(LPS) consisting of O protein-antignes attached to lipid A endotoxins
- O protiein/antigens distinguishes bacterial sp. from each other by conferring antigenic specificity(differences in O proteins)
- lipid A(endotoxin) are toxins released into the GI tract or bloodstream of host upon bacterial cell death or lysis, poisonous to host causing symptoms of fever,diarrhea or shock
which medically important genera are acid-fast bacteria
- Microbacterium Tuberculosis
- Microbacterium Leprae
- lipid rich mycelia acids found in CW of acid-fast bacteria make them somewhat resistant to the gram stain.
- thus these bacteria are stained with the acid-fast staining technique instead of the gram stain technique
gram non-reactive bacteria
- do not take up the gram stain in all b/c they lack a PG layer
- which bacteria do not have cell walls? mycoplasma
cell membrane/plasma membrane
- the innermost phospholipid bilayer that encloses the cells cytoplasm
- function: transport materials into and out of the cell via diffusion, facilitated diffusion, active transport and osmosis
osmosis
the diffusion of water across a semipermeable membrane to an area of greater solute concentration, greater osmotic pressure, until equilibrium. the greater the solute concentration of a solution, the greater is its osmotic pressure
osmotic pressure
- the water absorbing capability of a solution
- solute, salt, concentration of solution surrounding bacterial cells are relative to the salt concentration inside the cells.
- this will determine the net flow of water into or out of the cells
iso-tonic solution
-no net flow of water across cell membrane
hyper-tonic solution
-net flow of water out of CM, cell shrinkage(plasmolysis)=cells die
hypo-tonic solution
- net flow of water into CM
- cell swells and may burst(osmolysis)=cell die
cell respiration
-is associated with enzymes in the cell membrane b/c bacteria(prokaryotes) lack mitochondria.
cytoplasm
-the dense watery gel like matrix(cytosol) containing dissolved organic and inorganic nutrients and cytoplasmic structures(nucleoid, plasmids, ribosomes and inclusions), all enclosed within the cell membrane.
Nucleoid
is an area in cytoplasm where a single, circular strand of DNA(chromosome) is found attached to the cell membrane
-plasmids: small, extrachromosomal circular strands of DNA found in certain species of bacteria, usually not crucial to bacterium survivl
Ribosomes
consist of two subunits(small or large)
- each consist of ribosomal RNA + proteins, subunits = 70s
- function: site of protein synthesis
inclusions
-are intracellular concentrations of reserve deposits(usually E reserve)
-found in certain species of bacteria
types:
1. metachromatic(inorganic phosphate) granules
2. polysaccaride(glycogen or starch)
3. lipid
4. sulfur inclusions
bacterial endospores
-are special dormant cells formed by some bacteria when essential nutrients are unavailable in their environment(ex. carbon or nitrogen) spore-forming bacteria are found in the soil and intestines of animals
medically important species of bacteria that are sporeformers and the diseases they cause
- Clostridium perfringens(cause of gas gangrene)
- Clostridium tetani(cause of tetanus/lock jaw)
- Clostridium botulinum(cause of botulism)
- Clostridium difficile(cause of antibiotic associated diarrhea=pseudonmembranous colitis)
- Bacillus anthracis(cause of anthrax)
function: survival in adverse conditions
why are endospores resistant to chemicals, radation,freezing, antibiotics and heat treatment?
impervious spore coat and cortex
what treatment is most effective in killing bacterial endospores?
autoclave(steam heat under pressure)
sterilizes
structure of endospore
- spore coat: thick outer protein layer
- spore cortex: PG layer between spore septum and dehydrated inner core containing DNA, RNA, ribosomes, enzymes and a few important molecules
sporulation
the process of endospores formation within the vegetative cell
germination
the return of spores to their vegetative state
stages of sporulation aka sporogenesis
- ingrown cell membrane(spore septum) isolates newly replicated chromosomes and small amount of cytoplasm(asymmetrical/unequal divisions of vegetative cell)
- spore septum(double layered membrane) encloses chromosomes to form forespore
- a thick layer of PG is laid down between the two spore septum membrane layers to form a thick cortex
- thick spore coat of protein forms around the outer membrane of the spore septum
- vegetative cell is degraded and endospore is released into the environment
distinguish between the vegetative cell and the endospore
-vegetative cells are metabolically active, dividing cells endospores are metabolically inactive, non-dividing, dormant, dehydrated resistant cells
how long can endospores survive
-forever
which bacterial structures are found in all bacterial cells
- cell membrane
- ribosomes
- DNA
- cytoplasm
