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How do eukaryotic cells (amoeba) differ from prokaryotic cells (bacteria) in terms of growth and nutrition?
- eukaryotes - get nutrients from absorption, ingestion, transport
- prokaryotes - don't really get bigger; split; go from 1 to 2
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What are the inorganic nutrients bacteria need? Organic?
- inorganic - metals, salts, gases, water
- organic - proteins, carbs, lipids
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What are the two categories of bacteria in terms of how they obtain carbon?
- autotrophs - CO2 (made by themselves)
- heterotrophs - proteins, carbs, lipids (get from others)
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What is the energy source for photoautotrophs and photoheterotrophs?
light
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Macronutrients play principle roles in what? They are required in what quanitites? Examples?
cell structure & metabolism; required in large quantities (ex = proteins & carbs)
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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)
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Putting a bacteria from optimum to cold does what?
You don't kill bacteria, just stop it from growing (slows it down)
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What do phychrophiles have that make them resistant to freezing?
certain proteins and are genetically made
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What is the conversion of hydrogen sulfide into food?
chemosynthesis
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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).
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In the heat vents miles below the water surface, bacteria live as symbiotes in _____.
tube worms (tube worms have no digestive system)
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What happens to our proteins at extreme heat?
They are denatured
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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.
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The ____ pressure of an organism can change with the addition of salts or sugars.
osmotic
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Where would you find high O2 tension/obligate aerobes?
blood, lung, kidney
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Where would you find low O2 tension /obligate anaerobes?
intestines
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Tissue cut during trauma becomes anaerobic or aerobic?
anaerobic
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What is the increase in bacterial numbers due to binary division?
bacterial growth (growth exponentially)
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What is the term for the time for a cell population to double? (1 to 2)
Generation Time
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What happens in the lag phase of growth?
- getting started
- lasts about 5 hours
- cells increase in size
- no cell division
- increase in metabolic activity
- synthesis of cell compenents
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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
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What is the stationary phase of growth?
- plateau
- 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
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What happens in the death phase of growth?
the number of dying exceeds the number of new cells formed
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What is in vitro vs. in vivo?
- in vitro = in a test tube
- in vivo = in the body
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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.
exponential
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cells that are not growing are not ___ to disinfectants and antimicrobials.
susceptible
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What is acute vs. chronic infection? Examples?
- Acute:
- - rapid onset
- - ex = strep throat and e coli (20 minutes)
- Chronic:
- - take months before recognized
- - slow generation (12 hours)
- - ex = TB
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How long does it take for antibody production?
7 days
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A ____ amount of bacteria is often needed to show symptoms, but even one bacterium can cause disease.
large
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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.
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Bacteria are key in the cycling of ____ in ecosystems.
nitrogen
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What is a biofilm?
bacterial community composed of microcolonies of bacteria surrounded by a gooey extracellular matrix that they secrete
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What is the signaling process of neighboring bacteria?
quorum sensing (autoinducers)
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With exposure to bleach, the cells on the outside of the biofilm ___ while the cells inside ____.
die; live
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Where can some biofilm infections be found?
- implants
- artificial joints
- urinary cathetar
- dental cavities
- slimy contact lenses
- right after surgery
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How does a biofilm overwhelm the immune system?
the cells turn on toxin production all at once
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In relation to biofilms, how does cystic fibrosis work?
- forms biofilm
- neutrophils (immune system cells) and microphages can't come in
- dispersal not uncommon
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What is a biofilm-forming bacteria?
pseudomonas
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What are some ideal characteristics of disinfectants?
- rapid action
- maintained efficacy in presence of protein or blood
- low toxicity
- user safety (user friendly; not corrosive to hands, etc)
- material combatibility
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What are the 3 microbial control methods?
- physical agents
- chemical agents
- mechanical removal methods
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What is COMPLETE removal of all viable organisms?
sterilization
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What is the hygiene hypothesis?
not letting us build immunities because we are too obsessed with cleanliness
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what is a sterilizing gas used in an autoclave?
ethylene oxide
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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)
- microbial characteristics
- environmental influence/presence of organic matter (fats & proteins protect; heat is more effective with low pH)
- time of exposure (spores longer than vegetative cells)
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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)
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an autoclave must occur within a ____
vacuum
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What is the removal of water (i.e. instant coffee)
lyophilization
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what are forms of dry heat when it comes to controlling microbes?
burner/incinerator (120C for more than 2 hrs)
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what contributes to bacteriostatic effects & decreased chemical reactions
cold - refrigeration
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What is radiation?
the destruction of DNA
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what does this symbol represent?
cold pasteurization = irradiated food (ionizing radiation)
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What does ionizing radiation use?
gamma rays and high energy electron beam
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What does non-ionizing UV entail?
produced by electric currents passing through special lamps (for air and surfaces)
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What is a major problem with radiation?
you kill EVERYTHING and medial/radiation waste
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Iodine and chloride are what?
halogens
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What does bleach do to enzymes and proteins?
unfolds them
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What does hypochlorous acid do to proteins in the cell membrane?
oxidize them
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How do you make a 10% bleach solution?
1 part HClO and 9 parts H2O
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What are the most resistant microbes? the least?
- most - prions, spores
- least - viruses with lipid envelopes, gram + bacteria
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what is harder to kill, gram pos or gram neg bacteria?
gram neg (because of the outer membrane)
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What are some primary protection barriers?
- hoods (air flows up and out)
- masks
- gloves
- gowns
- booties
- breathing apparatus
- special showers
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what are some examples of inorganic nutrients?
- metals and their salts (magnesium sulfate, ferric nitrate, sodium phosphate
- gases (oxygen, CO2)
- water
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What are some examples of organic nutrients?
methane (CH4), carbs, lipids, proteins, nucleic acids
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Where in the body are there aerobic conditions? (high oxygen tension)
blood, lungs, brain, kidney, bone
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Where in the body are there anaerobic conditions? (low oxygen tension)
intestines, clostridium (lives in intestinal tract, causes C diff)
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what can make an anaerobic condition?
- narrowing of blood vessels
- trauma (breaking cap beds)
- surgery
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