mikrobiyoloji Flashcards
bacteria size- visibilty
1-2 microns smallest 0.1-0.2 mikrom larger bacteria many microns length visible with the light microscope animal and plant cells are much larger thant bacteria
microbial taxonomy
comprises three distinct but highly interrelated disciplines:
classification
nomenclature
identification
applied to all living entities
taxonomy provides a consistent means to classify, name and identify organisms
microbial classification
the organization of microorganisms that share similar morphologic physiologic and genetic traits into spesific groups
classification in hierarchial order from smaller to larger
species genus family order class division kingdom
which taxonomic groups do we interest in biology?
species and genus
species
tür
most basic taxonomic group
they share many common physiologic and genetic features (stracture, pathology, immunology…)
there are subspecies: they share spesific but minor characteristics
taxonomic importance, practical utility
in diagnostic microbiolgy: usually limited value
3 subspecie types
biotype
serotype
genotypes
nomenclature
the naming of microorganisms according to established rules and guidelines
genus and species are important
binomial (two-name) stystem
organism label rules
two pars
genus- always capitalized
species- never capitalized
written with italics or underlined
can be used with upper form of first letter of genus with . and full species name
exp: Genus species and G. species
informal designation used too but not italicized or capitalized exp: staphylococci, enterococci…
eukaryote major groups
algae fungi(yeasts,molds) protozoa plants animals (greek for true nucleus)
prokaryote major group
bacteria archae blue-green algae (greek for primitive nucleus)
eukaryote size
> 5 mikrom
prokaryote size
0,5-3,0 mikrom
eukaryote prokaryote nucleus difference
euk has classic membrane
prok hasnt got nuclear membrane
eukaryote chromosome type
strands of DNA, diploid genome
human contains 3 billion base pairs
prokaryote chromosome type
single double-stranded, circular DNA, haploid genome
contains 5 million base pairs
eukaryote prokaryote ribosome difference
eukaryote 80s (60s+40s) prokaryote 70s (50s+30s) (smaller) according to location of ribosomes
eukaryote prokaryote cytoplasmic membrane difference
eukaryote contains sterols
prokaryote doesnt contain sterols
eukaryote prokaryote cell wall difference
eukaryote only present for fungi
prokaryote: a complex structure containing protein, lipids, peptidoglycans (meshlike)
eukaryote prokaryote reproduction difference
eukaryote: sexual and asexual
prokaryote: asexual (binary fission)
eukaryote prokaryote movement difference
eukaryote: complex flagellum if present (kamçı)
prokaryote: simple flagellum if present
eukaryote prokaryote respiration(solunum) difference
eukaryote: via mitochondria
prokaryote: via cytoplasmic membrane
archaebacteria
resemble bacteria in most ways but represent a domain unique from bacteria and eukaryotes
eukaryote prokaryote survivng difference
bacteria is more resistent than eukaryotic cells
bacterial classification
by their macroscopic and microscopic appearance
by characteristic growth and metabolic properities
by antigenicty
by genotype
macroscopic and microscopic distinction
by growth characteristics and different nutrient and selective media
colony
bacteria grow in colonies
eanch colony is a city of million or more organisms
different types of shapes of bacteria
cocci
bacilli rods
curved
spiral
bacteria types for the abilty to retain Gram or other stains
Gram-positive
Gram-negative
Acid fast positive or negative
aggregates
some bacteria form
grapelike clusters or diplococcus(two cells together)
Gram stain
rapid, powerful, easy test
used to distinguish between the two major classes of bacteria
used to develope initial diagnosis
used to initiate therapy based on inherent differences in the bacteria
metabolic features of bacteria
anaerobic-aerobic
bacterial classificication according to antigenic features / serotyping
serotyping: using antibodies to detect characteristic antigens very specific but not frequently used *too difficult to grow *too dangerous *need to be identified rapidly(hızla)
genetic distinction of bacteria
the most precise (kesin) method for classifying bacteria
by analisis of genetic material
gram positive bacteria color
violet-blue
gram positive bacteria types
bacilli
cocci: streptococcus, staphylcoccus
branching filaments
gram negative bacteria color
red
gram negative becteria types
diplococci
coccobacilli
bacilli
comma shaped
bacteria types that cant be characterized by Gram reaction
mycobacteria
obligate intracelluar and nonculturable bacteria
cell wall deficient bacteria: mycoplasma, ureaplasma
spirochetes
what layers surround the cytıplasmic membrane in cell walls?
rigid peptidoglycan (murein)
cell wall in Gram positive bacteria
thick multilayered cell wall consisting mainly of peptidoglycan
degraded(bozulmak) by treatment with lysozyme
*includes proteins, teichoic and lipoteichoic acids and complex polysaccharides(C polysaccharides)
why is peptidoglycan is essential for cell wall
for structure
for replication
for survival in the normally hostile conditions
protoplast
the structure formed by the removal of the cell wall
teichoic acids
water soluble, anionic polymers of polyol phosphates
lipoteichoic acids
fatty acids and anchored in cytoplasmic membrane
cell wall in Gram negative bacteria
cell walls are more complicated than gps
contains two layers external to the cytoplasmic membrane
no teichoic or lipoteichoid acid
has outer membrane
addition of lysozyme to GN cells with a disrupted outer membrane produces spheroplasts
outer membrane
external to the peptidoglycan layer
uniqe to GNs
connected to cytoplasmic membrane at adhesion sites and tied to peptidoglycan by lipoprotein
periplasmic space
area between the external surface of the cytoplasmic membrane and the internal surface of the outer membrane
contains components of of transport systems and variety of hydrolytic enzymes
these functions are important to the cell for the breakdown of large macromolecules
lipopolysaccharide (LPS)
also called endotoxin
a powerful stimulator of innate and immune responses
*induces fever and can cause shock
*Shwartzman reaction (disseminated intravascular coagulation=DIC) follows the release of large amounts of endotoxin into the bloodstream
neisseria bacteria shed a large amounts of related molecule, lipooligosaccharide (LOS), resulting in fever and severe symptoms
contains transmembrane proteins?
porins
form pores allowing the diffusion of hydrophilic molecules less than 700Da in mass through the membrane
protoplasts and spheroplasts
laboratory generated entities
have everything expect cell wall
spheroblasts
a bacterium or plant cell bound by its plasma membrane, the cell wall being deficient or lacking and the whole having a spherical form
spherical shape assumed by gram negative bacteria
protoplasts
spherical shape assumed by gram positive bacteria
L forms of bacteria
arise spontaneously
lack cell wall
cytoplasmic structure of bacteria
contains DNA chromosome, messenger RNA (mRna), ribosomes, proteins and metabolites
unlike eukaryotes, the bacterial chromosome is a double stranded circle, isnt contained in a nucleus but in an area called nucleoid, is haploid,
Dna doesnt have histons
dna doesnt form nucleosomes
contain plasmids
plasmids
eukaryotes dont have
smaller, circular, extrachromosomal DNAs
not essential but adds extra functions, residency(antibiotic olayı)
why is transcription and translation are coupled in prokaryotes?
because there isnt a nuclear membrane,
iki olay arası çok kısa sürüyor
what is mycoplasma difference to prokaryotes in membranes?
mycoplasmas contain steroids
capsules
loose polysaccharide or protein layers closely surrounding bacteria
slime layer
loosely adherent material around bacteria
the capsules or slime layers also called what?
glycocalyx
the bacteria that produces a polypeptide capsule
bacillus anthracis
india ink
with this capsules can be seen
capsule and slime functions
unnecessary for the growth of bacteria
very important for survival in the host
poorly antigenic and antiphagocytic factor
major virulence factor
biofilm
external structure
a polysaccharide structure produced and secreted by bacteria when quarum reached
bu halde antibiyotikler dah zor etki eder, fagosite olmaları zorlaşır
supports growth, establishes a bacterial community and protects bacteria from antibiotics and host defenses
tooth plaque produced by s. mutans is biofilm exp
quorum
sufficiency numbers of bacteria
quorum sensing
a system used by bacteria to coordinate gene expression according to the density of their local population
çoğunluk sağlanınca organizasyon biraz değişir replikasyon duru başka şeyler yaparlar
biggest infection in the world
diş çürüğü
flagella
ropelike propellers made up of helical coiled protein subunits: flagellin
anchored in the membranes through hook and basal body structures and driven by membrane potential
provide motilty for bacteria
allows chemotaxis( cell to swim toward food or away from posions)
fimbrae(pili)
hairlike structures on the outside of bacteria
composed of protein subunits(pilin)
smaller than flagella
doesnt coiled in structure
promote adherence to other bacteria or to the host
attach to target cells
alt. names: adhesins, lectins, evasins, aggressins
important virulence factor for colonization and infection of the urinary tract
adhesine
adherence factor
lectins
tips of fimbrae
protein structure binding to specific sugars
F pili
sex pili
bind to other bacteria
a tube for large segments of bacterial chromosems transport btween bacteria
mycobacteria
surrounded by a waxlike lipidcoat of mycolic acid, cord factor, wax D, sulfolipids
staining acid-fast
chalydia and mycoplasmas has no peptidoglycan cell wall
spores
under harsh enviromental conditions these bacteria can convert from vegetative state to dormant state or spore
no metabolic activity
doesnt replicate
some GP form but never GNs
bacillus and closridium
the location of spore within a cell is characteristic of bacteria
assist in identification of bacterium (central terminal subtrrminal)
allows bacteria to exist in suspended animation
contains complete copy of chromosome
bare min essential proteins ribosomes
high concentration of calcium bond to dipicolinic acid
has inner membrane, two peptidoglikan layers outer keratinlike protein coat
can survive for decadeas
looks refractile(bright) in microscope
