naming and classifying bacteria quiz Flashcards
what are infectious diseases caused by
viruses, bacteria, fungi , parasites
most bacteria is not is not dangerous
yes
clinically significant
bacteria that are linked to disease
like other species, how are bacteria named
by binomial nomenclature
what is binomial nomenclature
two words: genus and species
typically many species for
for one genus
binomial nomenclature should always be
italicized in print
underlined in writing
first letter of genus in binomial nomenclature
capitalized
species name in binomial nomenclature
entirely lower case
there are often many species
in a genus
members of a species can _____ through
vary a lo through horizontal gene transfer
what is the genetic material of bacteria
one large circular chromosome… called plasmid
why are bacteria much harder to classify tan more complex species
horizontal gene transfer
horizontal gene transfer
passing of DNA into bacteria
three main ways of horizontal gene transfer
transformation
transduction
conjugation
transformation
“naked” DNA is absorbed by bacterium and worked into its DNA
transduction
DNA is injected by a bacteriophage
bacteriophage
bacteria-infecting virus
conjugation
DNA is spread from bacterium to bacterium through(cell to cell contact) sex pilus
horizontal gene transfers caused there to be many
many strains of any species
different strains of a species can be very unique…..
VERY unique
in most cases of bacteria; inheriting just one gene will a grant a bacterium….
- resistance to certain antibiotics
- the ability to synthesize a new nutrient
- or the ability cling to a new surface
metric by which bacteria are classified
- color
- morphology
- flagellation
- staining
- growth on various agars
- oxygen dependence
- other habitat preferences
- spore formation
how do we classify bacteria w color
bacteria secrete pigments or colored particles, they are sometimes fluorescent
colors can also be used to identify
microbes
classifying using morphology
classified with their shape
(rounds) a circle
cocci
two round circles
diplococci
pill shape
coccobacilli
rod-shaped
bacilli
two other shapes
curved and spiral
in many cases the name of the genus comes from the
shape of the bacterium
curved bacteria often called
vibrio
many bacteria have flagellation…
to help them move
flagellation comes in what forms
monotrichous
lophotrichous
amphitrichous
peritrichous
monotrichous
just one flagellum
lophotrichous
just one “tuft” of flagella
amphitrichous
having flagella on both sides
peritrichous
surrounded by flagella
flagella are made of what
flagellin
classifying with stain
results of gram stain
on a gram stain purple
is a positive result
what bacteria usually have a purple stain
bacteria have thick layers (usually 30-40 layers) of peptidoglycan
on a gram stain pink
is a negative result
what bacteria usually has a pink stain
bacteria usually have much thinner layers of peptidoglycan, as thin as 1-2layers
some bacteria don’t stain with a gram stain
especially ones that grow in eukaryotic cells
bacteria are grown in cultures on
agar
agar
gel-like substance
agars can be packed with
various substances like antibiotics, nutrients, blood
classifying with agars
depending on how they grow on those plates
example of a special type of medium (agar)
blood agar
blood agar
bacteria are plated with blood to see what happens
things that can happen with blood agar
gamma hemolysis
alpha hemolysis
beta hemolysis
gamma hemolysis
means that bacteria do not break blood
alpha hemolysis
means that the bacteria partially break blood
beta hemolysis
means that the bacteria fully break blood
blood agar can be very
important diagnostic tool… especially for Streptococcus species
oxygen is required
for human cells, not all bacteria
when can oxygen be bad
when it forms toxic compounds such as peroxides or superoxides
classifying with oxygen dependence
classified by their relationship
with oxygen
types of relationships with oxygen for bacteria
obligate anaerobes
obligate aerobes
facultative anaerobes
aerotolerant bacteria
obligate anaerobes
bacteria that can only survive if oxygen is absent
obligate aerobes
bacteria that can only survive if oxygen is present
ex obligate anaerobes
Clostridium ( cause of gangrene )
ex obligate aerobes
Pseudomonas
facultative anaerobes
bacteria that prefer to use oxygen-based respiration but can also survive in oxygen-free homes
ex of facultative anaerobes
Staphylococcus, Streptococcus)
aerotolerant bacteria
bacteria that do not use oxygen-based respiration but can survive if oxygen is present
classifying with other preferred living conditions
based on preferred living arrangements
different preferences for bacteria living conditions (temp)
thermophiles
psychrophiles
mesophiles
thermophiles
like it hot
psychrophiles
like it cold
mesophiles
body temp
different preferences for bacteria living conditions (acidity)
acidophiles
alkaliphiles
neutrophiles
acidophiles
like it acidic
alkaliphiles
like it basic
neutrophiles
like it neutral
body temp
37 degrees C
blood pH
7.4
classifying with spore formation
spores or no spores
special survival mechanism of some bacteria
ability to form endospore
bacterial cells that can form an endospore
divide and then wrap the important stuff inside a thick double-layered cell wall and lay dormant until conditions turn more favorable
bacteria that can form an endospore are immune to
to many things like extreme temperature and can wait years before reactivating