micro final
what is used to treat microbe infections
antibiotics
what is selective toxicity
killing harmful stuff, w/o damaging the host
3 classifications of antibiotics
natural, synthetic, semi-synthetic
what type of inclusions store energy
metachromatic, polysaccharide,and sulfur granules & lipid inclusions
bacillus and clostridium have what
endospores
bacteria that produce endospores regrow into what
vegetative bacteria
3 locations of endospores
terminal, sub-term, and central
structure of endospore
exosporium, spore coat, cortex, core
what is sporulation
poor env. triggers gene change, turns veg cell into endospore
steps of germenation
activation (cut open spore)
germination (take in H2O and germ. agents)
outgrowth (makes new veg cells)
3 physical requirements for bacterial growth dynamic
temp, ph, osmotic pressure
what is a cardinal temperature
has min, optimal, max temp (like to be at optimal)
what are the classifications of philes
psychro (cold), meso (mod), thermo (heat)
what temp is the danger zone
15-52
what is pasteurs chickens exp.
too high body temp for anthrax to colonize (humans-37, vs chickens 42)
what are the steps of bacterial milking
grow bacteria in - water balance
respond & produce ectoine
return to + water balance & get rid of ectoine to env.
other than binary fission, bacteria grow by a process called:
budding; unicellular yeast, bump forms and breaks off to make new cell
binary fission process:
replication, wall and memb divide, p. memb forms around DNA, seperation
_____ happens in an enclosed system with a fixed amt of nutrients
batch culture
bacterial growth curve for batch culture
lag, log, stationary, death
what phase of b. growth has no growth and has a variable length
lag phase
what phase of b. growth do cells start to divide and give us the / line and depends on generation time and env. conditions
exponential/ log phase
stationary phase does what?
slows down growth rate
death phase does what
cell death, endospore start sporulation
continuous culture process is:
a way to keep population of bacteria in one specific stage of growth curve for long time
primary and secondary metabolites
primary : produced as soon as bacteria grow (ex: big turkey dinner)
secondary: produced after time of growth, usually takes place after stationary phase (ex: turkey soup, made w leftovers)
dimitri iwanowski worked on what
tobacco plants and filtered through Chamberland filter (filtrate=infectious), caused by "small bacteria"
who reffeered to agent as "filterable virus" and found the agent in viruses were not bacteria because they had different behaviours
martinus beijerinck
what did wendell stanley do
purified and crystalized tobacco mosaic virus
_____ were used for growing vaccines
eggs
what virus didn't grow in eggs
poliovirus
what virus needed iron lung
poliovirus
what kind of cell lines are useful for 2-5 generations
primary cell lines
how many generations are virus-sensitive in low passage cell lines
20-50
these obligatory intracellular parasites require living host cells to replicate
viruses
true or false: viruses contain DNA and RNA
false, they can only have 1 not both
within a virus, what surrounds nucleic acid
a protein coat
a host range is determined by
required specific attachment receptors on host cell that match virus receptors
how does an endospore core differ from a vegetative cell
-core contains dipicolinic acied
-stablizies DNA against heat denaturation
-reduces water availability
-makes calcium dipicolinate
-pH in core is 1 unit lower
-high levels of SASP's
what is a high energy form of oxygen
singlet oxygen
what is a carotenoid pigment
acts as a catalyst to break down singlet O2 to become less toxic
how do obligate aerobes grow
in areas of high O2 concentration (not at bottom of tube)
what are both aerobic and anaerobic but grow better when O2 is present
facultative anaerobes
obligate anaerobes grow in:
absence of O2, CANNOT TOLERATE O2
what type of anaerobe does oxygen not affect
aerotolerant anaerobes
micro aerophiles grow in:
low [O2]
what is a cardinal temp
min, max, and optimal
what temp is danger zone
15-52
acidophiles:
low pH
alkaliphiles:
high pH
a closed system that keeps things moving is called
continuous culture process
how were viruses put together
dimitri: tobacco, grind and filter through chamberland "small bacteria"
beijerinck: not bacteria, behaved differently "filterable virus"
wendell stanley won a nobel prize for what
purifying and crystalizing tobacco virus
what is an example of a helical virus
ebola
what is an example of an enveloped virus
influenza
how many types of hemagglutinin are there
18
how many types of neuraminidase are there
11
what is a capsid
protein coat surrounding nucleic acid
pros and cons of envelopes
pros
-hide from immune cells
-helps fuse w host
cons
-easily damaged
-sensitive to pH and disinfectants
-lose memb. and become non infectious
how do we name viruses
family-> genus->species
5 steps of viral replication LYTIC CYCLE
attachment: collide phage w bacteria
penetration: tail release into lysosome&inject into host
biosynthesis: early mRNA, DNA replication, late mRNA
maturation: assemble viral components
release: host=lysed and releases new progeny
how is lysogeny diff than lytic
-uses recombination to become a prophage
-many cell divisions
-can be lost and enter lytic cycle
-daughter cells become lysogenic
-occurs in temperate viruses
what is an eclipse period
when there is no infectious viruses present
what period follows the increased number of infectious virions until release from host
rise period
animal virus replication
attachment: receptors on surface of memb of host, receptors of virus are all over surface (diff ways to contact)
penetration: uncoated genome released from capsid, membrane fusion, endocytosis
biosynthesis: replication of DNA is easy, diff for +/- ds or ss RNA
maturation: late genes help assemble new copies
release: naked- lysis, envelopes- concurrently
dsRNA (rota) variation in biosynthesis
+ strand=mRNA for translation
+ssRNA (polio) biosynthesis variation
ss=mRNA, -RNA strand= +ssRNA copies
-ssRNA (rabies) biosynthesis variation
RNA polymerase transcribes +RNA from -RNA
+RNA used as mRNA to make proteins
retroviruses (HIV)
use reverse transcriptase, dsDNA makes provirus (irreversible)
influenza A
found in birds, makes hybrid virus, V1+V2=V3
what animal is used as a mixing vessel
pig
spanish flu is also known as
H1N1
what is an antigenic drift
mutation in virus RNA, why we need yearly flu shot
what do antiviral ion channel blockers do
prevent uncoating so replication doesn't happen
what do antiviral neuraminidase inhibitors do
prevent new viruses from being released from host
what is an example of a continuously infectious infection
HEP B
example of partial infectivity infection
adenovirus
what is a latent viral infection
when the virus stays in equilibrium and doesn't cause disease
what are 2 examples of a latent viral infection
-Herpes (HSV-1 and HSV-2)
-Varicella-Zoster (chickenpox and shingles)
what are the 2 stages of viral reactivation
resumption and replication
a viroid only has_____ and no ______
ssRNA, protein
a prion is a _____ molecule
protein
what are the 4 types of CJD
-sporadic (mutation in Prnp)
-familial (inherited mutated gene)
-iatrogenic CJD (medical transfer of prions)
-new variant (BSE-contaminated beef)
difference between PrPc and PrPsc
c- helix>pleated sheets
sc-pleated sheets>helix
what is a mutation
change in base sequence (A,G,C,T)
_____ occurs when 1 or more bases are inserted or deleted in a DNA sequence
frame-shift mutation
dimer production is:
exposure to UV, damaged DNA removed, polymerase fills gap, ligase seals&joins old and new DNA
what 2 things are required for bacterial recombination
donor and recipient cell
3 forms of bacterial recomb.
transformation: picks up free DNA
conjugation: cell-cell transfer of genetic material
transduction: transfer chromosomal material by bacteriophage
what is griffiths experiment
S (capsule) and R (no cap)
Live S= kills rat
Live R= no effect on rat
Heated S strain= no effect on rat
Live R&heated S= kills rat
3 types of conjugation
F plasmid: F+ and F- connected by sex pilus, transfers plasma DNA
Hfr cell: plasmid knicked at oriT and merges into chromosome, transfers bacterial DNA and some plasmid DNA
F' plasmid: same as F, but carry chromosomal genes
what is generalized transduction
-when any portion of genome has a good likelihood of being transferred as any other part
-bacteria in lytic cycle gets a transducing particle
what is specialized transduction
-when specific regions are more likely than others to be transferred (only temperate bacteriophages)
-uses lysogeny
what microorganism is most resistant to control
prion
what microorganism is least resistant to control
enveloped virsuses
what is the best example of non-ionizing radiation
UV light (260nm is most effective wavelength)
disc diffusion test shows:
zones of inhibition (antibiotic sensitivity)
antibiotic assays determine _____
sensitivity of microorganisms to antibiotics
what % of particles can HEPA filters remove in 0.3um
99.97%
the TUBE with the lowest [antibiotic] that shows no visble growth is:
MIC- minimum inhibitory concentration
the lowest concentration sample w no growth on AGAR PLATE is:
MBC- minimum bactericidal concentration
what are the 5 modes of action of antibiotics
-inhibition of cell wall synthesis (penicillin- prevents NAG/NAM from linking)
-inhib. of protein synthesis (tetracyclin - 30S subunit, tRNA and mRNA attatchment & erythromycin - 50S subunit, translocation)
-injury of plasma memb (polymyxin B- attack phospholipids)
-inhib. of nucleic acid synthesis (quinolones- block replication)
-inhib. of essential metabolite synthesis (sulfonamides- mimic PABA)
4 mechanisms of antibiotic resistance
-bacteria destroy drug
-prevent drug from penetrating
-target site
-increase rapid pumps
true or false: antibiotics work on viruses
false