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57 Cards in this Set

  • Front
  • Back
Classify microbes into 5 groups on the basis of preferred temperature range
Psychrophiles, Psychrotrophs, Mesophiles, Thermophiles, and Hyperthermophiles
Identify how and why the pH of culture media is controlled...
They often produce acids that interfere with their own growth when cultured, so chemical buffers are included to neutralize and maintain proper pH
Importance of osmotic pressure to microbial growth?
used to preserve foods and prevent the growth of microbes
name a use for each of the four elements (carbon, nitrogen, sulfur, and phosphorus) needed in large amounts for microbial growth.
carbon; structural backbone
nitrogen; synthesizes protein and helps DNA and RNA synthesize
sulfur; synthesizes sulfur-containing amino acids and vitamins
phosphorus; synthesizes nucleic acids and phospholipids of cell membranes
define nitrogen fixation
use of gaseous nitrogen (N2) directly from atmosphere to synthesize
Explain how microbes are classified on the basis of oxygen requirements.
Require oxygen to live: Obligate aerobes
Ability to grow in absence of oxygen: Facultative anaerobes
Can not live where oxygen is present: Obligate anaerobes
Can not use oxygen to grow but they tolerate it: Aerotolerant anaerobes
Require oxygen but only grow in low concentrations: Microaerophiles
Identify ways in which aerobes avoid damage by toxic forms of oxygen,
- develop enzymes to neutralize it such as catalase which converts in to water.
-singlet oxygen is normal oxygen (o2) that has been boosted into a higher-energy state
Aerobe vs Anaerobe
aerobe requires molecular oxygen for growth and an anaerobe does not.
Describe the formation of biofilms and their potential for causing infection.
pillar like structures of slime with channels through water can carry incoming nutrients and outgoing waste.
-can be formed by fungi which are encountered in many disease conditions
chemically defined vs complex media.
Chemically defined medium is one whose exact chemical composition is known. Complex medium varies from batch to batch
What bacteria physically require:
temp, pH, osmotic pressure, atmospheric pressure
food preservative
Hydrogen ion concentration & ph
10^0 ---- 10^ -7 ------10^ -14

pH= -log[H+]
ph is a.... of the .... in....
the pH scale
Fermentation by Microbes end products
a lot of acidic and toxic products
lactobacillus acidophilus
-lactic acid producers
-aerotolerant anaerobe
-use it industrially in probiotics
-found in oral cavity, small intestine, and vag
osmotic pressure: isotonic solution vs. hypertonic solution
isotonic: solute concentration in cell is = to solute concentration of .85% NaCl (sodium chloride)
hypertonic: if concentration of solutes such as NaCl is higher in surrounding medium than in cell, water leaves cell and cell can not grow
Pseudomonas aeruginosa Biofilm
-lot of enzymes enabling it to have many potential hosts
-releases blue pigment when in a colony
Advantages of Biofilm
-doesn't dry out
-shares nutrients
-waste removal
-avoids host immune system
-resistant to antibiotics
-resistant to microbicides
-communication and group action
-shelter from environmental factors
-shares genetic material, conjugation
-works together on complex tasks(cow digestion)
-soil structure*
-Bonnie Bassler
-bacteria communicate with chemical signals
-used to identify whether or not they have enough bacteria
-lock and key mechanism
chemo (organic molecules for carbon)
hetero (eats, uses chemical source for energy)
troph (for nutrition)

-source of carbon, supple oxygen, and nutrients.
chemically complex medium:
-nutrients are in agar
-growth of heterotrophic bacteria
-"beef extract" and peptone (partially digested protein)
anaerobic bacteria culture:
-has to be in container
-needs armadillos to grow
Biocontainment: 4 levels
1) moderate precautions (goggles, gloves, aprons)
3) air circulation
4) sealed environment w/ negative atmospheric pressure (TB rooms)
Blood agars:
-50% sheep blood
-beta-hemolysis (break down of blood cells)
Mannitol Salt Agar
-both selective and differential
-S. auerus is halotolerant
-nutrition source to allow things to grow
Binary Fission:
2 cells become 4 > 8 >16 >32
phylum proteobacteria:
-gram - and chemoheterotrophic bacteria
-based on rRNA
-capable of growth at low levels of nutrition
-some agriculturally important
-some use less common nutrient substances
-some are pathogenic
-diverse, includes e.coli
-some predators
-some participate in sulfur cycle
phylum cyanobacteria
gram negative, autotrophic
phylum firmicutes
-gram positive, love G+C content
phylum actinobacteria
gram positive, high G+C content
Rhizobia sp.
-corn takes a lot of nitrogen from soil, rhizobia puts it back in
-takes atmospheric N2 and makes ions NH4 (ammonium) + NO-2 (nitrate)
-forms nodules on roots
-enters through root hair
-Proteobacteria (phylum) Alpha (class)
Agrobacteria sp.
-crown gall (plant tumor)
-plasmids are vectors
-gram -
-Proteobacteria (phylum) Alpha (class)
Neisseria sp.( 8 )
-responsible for gonorrhea
-exists as a diploid (mid division)
-fimbriae allow it to stick to things
-cross species
-Proteobacteria (phylum) Beta (class)
Pseudomonas sp. (sperm looking)
-opportunistic infection
-array of enzymes therefore can exist in many environments
--Proteobacteria (phylum) Gamma (class)
Enterobacteriales (Order)
-ex: e.coli, salmonella, e. aerogenes
-coli form -evdidence of fecal contamination
-Proteobacteria (phylum) Gamma (class)
Cyanobacteria (Phylum)
-gram negative
-"moving algae"
-gram negative
Bacillus sp.
-gram positive, low G+C***
-strain called "BT Kurstaki" -kills caterpillars
-Israeliensis- kills mosquittos
-BT genes- toxic crystal gene
-GMO- genetically modified
-Firmicutes (phylum)
Staphylococcus sp.
-adapt and have resistant strains quickly
-s. epidermidis, s. aureus
-Firmicutes (phylum)
Streptococcus sp.
-Rebecca Lancefield
-obligate anaerobes but aerotolerate
-only ferment
-Firmicutes (phylum)
lactobacillus sp.
-lactobacillus acidophilus -> "good" intestinal microbe
-lactic acid producing bacteria
-inhibits growth of other organisms, allowing them to grow despite metabolism
-Firmicutes (phylum)
Enterococcus sp.
-likes regions high in nutrients (intestinal tract, vag, oral cavity)
-Firmicute (phylum)
Mycoplasma sp.
-bacteria with no cell wall
-extremely small
-smallest self-replicating unicellular organism
-Firmicutes (phylum
Mycobacterium sp.
-needs acid fast stain
-wax coating
-gram negative
-Actinobacteria (phylum)
Streptomyces sp.
-Actinobacteria (phylum)
Pyrodictium abyssi
-from deep sea vents
-Archaea (domain)
-aerobic or facultative anaerobic, gram negative, non-endospore forming, rod-shaped bacteria that ferment lactose with acid and gas within 48 hours at 35 degrees Celsius
cocci that divide and remain attached in pairs
common name for bacterium in the family of enterobacteriaceae.
variation within a species