micro ch 5
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micro ch 5
micro ch 5
How do eukaryotic cells (amoeba) differ from prokaryotic cells (bacteria) in terms of
eukaryotes - get nutrients from absorption, ingestion, transport
prokaryotes - don't really get bigger; split; go from 1 to 2
What are the inorganic nutrients bacteria need? Organic?
inorganic - metals, salts, gases, water
organic - proteins, carbs, lipids
What are the two categories of bacteria in terms of how they obtain carbon?
autotrophs - CO
(made by themselves)
heterotrophs - proteins, carbs, lipids (get from others)
What is the energy source for photoautotrophs and photoheterotrophs?
Macronutrients play principle roles in what? They are required in what quanitites? Examples?
cell structure & metabolism; required in large quantities (ex = proteins & carbs)
Micronutrients/trace elements play principle roles in what? They are required in what quanitites? Examples?
enzyme function & maintaining protein structure; required in small amounts (ex = manganese, zinc, nickel)
Putting a bacteria from optimum to cold does what?
You don't kill bacteria, just stop it from growing (slows it down)
What do phychrophiles have that make them resistant to freezing?
certain proteins and are genetically made
What is the conversion of hydrogen sulfide into food?
The bacteria in your stomach live in a pH of 0.5. What do they do to survive?
Take attributes from the urea & make ammonia (basic).
In the heat vents miles below the water surface, bacteria live as symbiotes in _____.
tube worms (tube worms have no digestive system)
What happens to our proteins at extreme heat?
They are denatured
How do microbes eat radioactivity?
Rock contains radioactive elements that break down into water.
H2O2 is made.
H2O2 reacts with FeS2 to make SO4.
MIcrobes eat the SO4.
The ____ pressure of an organism can change with the addition of salts or sugars.
Where would you find high O2 tension/obligate aerobes?
blood, lung, kidney
Where would you find low O2 tension /obligate anaerobes?
Tissue cut during trauma becomes anaerobic or aerobic?
What is the increase in bacterial numbers due to binary division?
bacterial growth (growth exponentially)
What is the term for the time for a cell population to double? (1 to 2)
What happens in the lag phase of growth?
lasts about 5 hours
cells increase in size
no cell division
increase in metabolic activity
synthesis of cell compenents
What happens in the log phase (exponential phase) of growth?
cells dividing at a constant, exponential max rate
lasts about 10 hours (E. coli = 20 min)
rate determined by species and temp
What is the stationary phase of growth?
stop dividing (run out of nutrients, too many waste products, etc)
decreased growth rate (some are dying, some are growing)
viable cell count remains the same
What happens in the death phase of growth?
the number of dying exceeds the number of new cells formed
What is in vitro vs. in vivo?
in vitro = in a test tube
in vivo = in the body
The organism must be treated before it reaches the ____ phase, or else growth of the organism will be so fast that the host cannot keep up with the infection.
cells that are not growing are not ___ to disinfectants and antimicrobials.
What is acute vs. chronic infection? Examples?
- rapid onset
- ex = strep throat and e coli (20 minutes)
- take months before recognized
- slow generation (12 hours)
- ex = TB
How long does it take for antibody production?
A ____ amount of bacteria is often needed to show symptoms, but even one bacterium can cause disease.
What is the role of anoxic sediments in the environment.
Harbors archaea that produce methane.
Methane rises to top and is given to the bacteria in that zone.
Methane can be a source of carbon.
Bacteria are key in the cycling of ____ in ecosystems.
What is a biofilm?
bacterial community composed of microcolonies of bacteria surrounded by a gooey extracellular matrix that they secrete
What is the signaling process of neighboring bacteria?
quorum sensing (autoinducers)
With exposure to bleach, the cells on the outside of the biofilm ___ while the cells inside ____.
Where can some biofilm infections be found?
slimy contact lenses
right after surgery
How does a biofilm overwhelm the immune system?
the cells turn on toxin production all at once
In relation to biofilms, how does cystic fibrosis work?
neutrophils (immune system cells) and microphages can't come in
dispersal not uncommon
What is a biofilm-forming bacteria?
What are some ideal characteristics of disinfectants?
maintained efficacy in presence of protein or blood
user safety (user friendly; not corrosive to hands, etc)
What are the 3 microbial control methods?
mechanical removal methods
What is COMPLETE removal of all viable organisms?
What is the hygiene hypothesis?
not letting us build immunities because we are too obsessed with cleanliness
what is a sterilizing gas used in an autoclave?
What are some of the factors relating to the control of microbial organisms?
effect of initial load of microbes
number of microbes (the more there are, the longer it takes to kill them off)
environmental influence/presence of organic matter (fats & proteins protect; heat is more effective with low pH)
time of exposure (spores longer than vegetative cells)
an autoclave can kill vegetative cells and spores within ___ minutes; they are used to clean ____
15 minutes; solutions, dressings, equipment (medical--can't have plastic or rubber)
an autoclave must occur within a ____
What is the removal of water (i.e. instant coffee)
what are forms of dry heat when it comes to controlling microbes?
burner/incinerator (120C for more than 2 hrs)
what contributes to bacteriostatic effects & decreased chemical reactions
cold - refrigeration
What is radiation?
the destruction of DNA
what does this symbol represent?
cold pasteurization = irradiated food (ionizing radiation)
What does ionizing radiation use?
gamma rays and high energy electron beam
What does non-ionizing UV entail?
produced by electric currents passing through special lamps (for air and surfaces)
What is a major problem with radiation?
you kill EVERYTHING and medial/radiation waste
Iodine and chloride are what?
What does bleach do to enzymes and proteins?
What does hypochlorous acid do to proteins in the cell membrane?
How do you make a 10% bleach solution?
1 part HClO and 9 parts H2O
What are the most resistant microbes? the least?
most - prions, spores
least - viruses with lipid envelopes, gram + bacteria
what is harder to kill, gram pos or gram neg bacteria?
gram neg (because of the outer membrane)
What are some primary protection barriers?
hoods (air flows up and out)
what are some examples of inorganic nutrients?
metals and their salts (magnesium sulfate, ferric nitrate, sodium phosphate
gases (oxygen, CO2)
What are some examples of organic nutrients?
methane (CH4), carbs, lipids, proteins, nucleic acids
Where in the body are there aerobic conditions? (high oxygen tension)
blood, lungs, brain, kidney, bone
Where in the body are there anaerobic conditions? (low oxygen tension)
intestines, clostridium (lives in intestinal tract, causes C diff)
what can make an anaerobic condition?
narrowing of blood vessels
trauma (breaking cap beds)