Term
Psychrophiles
What are 2 groups? |
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Definition
cold loving, can grow at 0 degrees C
(strict psychrophiles: 0-15 degrees)
(psychrotrophs: prefer 20-30 degrees, responsible for low temperature food spoilage) |
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Definition
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Term
| Hyperthermophiles (aka extreme thermophiles) |
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Definition
prefer to grow above 80 degrees C
contains Archaea |
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Term
| Danger Zone for growth of most bacteria |
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Definition
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Term
| Ideal pH for most bacteria |
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Definition
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Term
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Definition
| bacteria that prefer acidic pH |
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Term
| Ideal pH for most molds and yeasts |
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Definition
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Term
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Definition
| bacteria that require high salt conditions |
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Term
Facultative anaerobes
(what are they and example) |
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Definition
prefer oxygen but can live without it. switch to using fermentation or anaerobic respiration
ex: E. coli |
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Term
Obligate anaerobes
(what are they and example) |
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Definition
can't tolerate oxygen
ex: agent of botulism, agent of tetanus |
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Term
Aerotolerant anaerobes
(what are they and example) |
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Definition
don't use oxygen for growth, but they tolerate it. inhibits growth of aerobic competitor species
ex: lactobacillus |
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Term
Microaerophiles
(what are they and example) |
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Definition
use oxygen, but prefer oxygen concentrations lower than present in air
ex: agent of food poisoning (campylobacter jejuni) |
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Term
| Who pioneered the use of ager as a growth medium |
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Definition
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Term
| To make anaerobic conditions, you need to add this agent to chemically remove the oxygen |
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Definition
| sodium thioglycolate, palladium pellets |
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Term
Capnophiles
(what are they, where in the body are they found, example) |
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Definition
bacteria that require high CO2 and low oxygen
found in digestive tract |
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Term
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Definition
| suppresses growth of unwanted species and encourages growth of others |
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Term
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Definition
allos one organism to be distinguished from others on teh same plate
ex: blood agar |
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Term
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Definition
| used to select rare organisms; works if the rare organism has an unique growth requirement |
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Term
| Method used to produce pure cultures |
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Definition
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Term
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Definition
Lag - prep for division, make DNA and enzymes
Log - exponential growth phase
Stationary - death equals new cells produces
Death - deaths exceed new cells produced |
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Term
Sterilization
Commercial Sterilization |
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Definition
Destruction of all microbes, including endospores
" except a few endospores |
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Term
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Definition
Destruction of non endospore forming pathogens
" on living tissue |
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Term
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Definition
| Removal of microbes from a limited area |
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Term
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Definition
| Treatment to lower microbial counts on eating and drinking utensils |
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Term
| Are Gram pos or Gram neg more susceptible to biocides? |
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Definition
| Gram positive because Gram negatives have the thick outer membrane |
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Term
| Thermal Death Point (TDP) |
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Definition
| lowest temperature at which all microorganisms are killed in 10 minutes |
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Term
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Definition
| minimal amount of time necessary to kill all organisms at a given temp |
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Term
| Decimal Reduction Time (DRT) |
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Definition
| time in minutes necessary to kill 90% of the bacteria at a given temp) |
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Term
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Definition
| Most organisms killed in 10 minutes |
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Term
| Autoclaving (high pressure and heat) |
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Definition
15 for 15
15 lbs per square inch at 121 degrees kills all organisms and endospores in 15 minutes |
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Term
| Modern methods for Pasteurization |
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Definition
High temp short time: 72 degrees for 15 seconds
Ultra high temp treatment - kills everything so it can be stored at room temp: 140 for 3 seconds, cooled rapidly to 74 |
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Term
| Method of microbial control for fluids that can't take high temperatures |
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Definition
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Term
| Methods of microbial control that are bacteriostatic, not bacteriocidal |
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Definition
| refrigeration, freezing, drying out, osmotic pressure differences |
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Term
| What method of microbial control is used to sterilize pharmaceuticals, lab plastiv ware, etc? |
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Definition
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Term
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Definition
first used by Joseph Lister
Rarely used now
Lysol
acts by disturbing plasma membrane |
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Term
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Definition
| triclosan in antibacterial soaps |
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Term
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Definition
chlorohexidine (surgical hand scrub)
acts by disturbing plasma membrane |
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Term
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Definition
Betadine, Isodine
Disinfection of skin |
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Term
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Definition
disinfection of drinking water, swimming pools, sewage
works by oxidizing and altering cells |
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Term
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Definition
Ethanol and isopropyl
works by protein denaturation and disruption of plasma membranes |
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Term
| Ethylene Oxide and Propylene Oxide |
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Definition
Chemical gases used for sterilizing
sterilizes without heat |
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Term
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Definition
extremely effecting for sanitization
kills endospores in 30 minute |
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Term
| Increasing order of hardest to kill of microorganisms |
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Definition
| gram positive, fungus, gram negative, endospores, prions |
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Term
| Who discovered the molecular structure of DNA |
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Definition
| Rosalind Franklin, Watson and Crick |
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Term
| What holds complementary strands of nucleotides together? |
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Definition
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Term
| Flow of Genetic information: 3 types |
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Definition
1. replication: parental cell --> daughter cell
2. transcription (DNA -> mRNA) and translation (proteins)
3. recombination (between 2 parental cells, partial DNA transfer) |
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Term
DNA Replication
(semi conservative) |
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Definition
1. helicase unwinds DNA double helix
2. RNA primers get in place
3. DNA polymerase attaches necleotides at 3' end and synthesis begins
4. leading strand copies continuously, lagging strand copies discontinuously (Okazaki fragments that are later fillled by DNA polymerase and joined by ligase)
error rate: 1 in 10^10 |
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Term
| Transcription: DNA -->RNA |
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Definition
1. RNA polymerase binds to DNA at promoter
2. transcription occurs until one entire gene has been converted to RNA
3. ends at terminator |
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Term
| Translation: protein synthesis |
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Definition
1. mRNA binds to ribosome at start codon AUG
2. tRNA that recognizes codons carries amino acids binds to start codon. more amino acids joined through peptide bonds
3. continues until stop codon is reached
sets of 3 nucleotides called codons specify each amino acid |
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Term
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Definition
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Term
| Transcription and Translation happen at the same time in what type of cells? |
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Definition
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Term
| What happens in eukaryotic cells after transcription? |
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Definition
| Ribozomes splice out introns so only exons are left |
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Term
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Definition
| block RNA polymerase from starting transcription at specified repressed gene |
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Term
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Definition
Jacob, Monod, Lwoff
Promoter is the recognition and attachment site of RNA polymerase
Operator - can be on or off |
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Term
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Definition
enzyme production is off until induced
ex: E coli using lactose instead of preferred glucose
inducer binds to repressor, repressor falls off operator site and transcription begins |
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Term
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Definition
enzymes usually turned on unless turned off
ex: excess tryptophan binds to inactive repressor and acts as new co-repressor, the combination of the 2 create an active repressor that binds to operator and blocks further transcription |
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Term
| Base substitution/point mutation |
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Definition
single base change in DNA
-amino acid change = missense
-creates stop codon = nonsense |
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Term
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Definition
one or more bases are lost/added from/to the DNA sequence
more harmful than point mutations |
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Term
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Definition
nitrous acid -> point mutations
nucleoside analogs -> base pair mismatches
benzpyrene or aflatoxin -> frame shift mutations |
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Term
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Definition
forms harmful covalent bonds between DNA bases
must be fixed with nucleotide excision repair
ex: thymine dimers (replication/trans stops at these sites; repaired by photolyases) |
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Term
| Spontaneous Mutation Rate |
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Definition
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Term
| Selecting Mutants - Positive Selection |
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Definition
introduce mutagen, only those with resistance will survice
ex: penicillin on a bacterial plate |
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Term
| Selecting Mutants - Negative Selection |
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Definition
velvet pad on 2 plates with different nutrients
those with holes - compared to original to find out mutation
auxotroph: mutant with a novel nutritional requirement |
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Term
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Definition
measures the ability of a lost function to be restored
(mutatnt speeds up process to restore lost function)
carcinogenic potential is determined by comparing the normal rate of reversion with the rate induced by the chemical agent |
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Term
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Definition
| exchange of genes between 2 sets of DNA |
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Term
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Definition
| transfer of DNA from one cell to another in solution |
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Term
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Definition
Frederick Griffith
mice and lethal bacteria - see notes |
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Term
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Definition
Ability to accept foreign DNA
(occurs naturally in very few groups of bacteria) |
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Term
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Definition
| transfer of genetic information from one bacterium to another by direct cell to cell contact |
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Term
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Definition
| DNA transferred by a bateriophage |
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Term
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Definition
"jumping genes" can move from one part of DNA to another piece of DNA on the same chromosome or another chromosome
found by Barbara McClintock in corn
simplest: insertion sequences
*introduce genetic change for evolutionary selection and can be manipulated to introduce mutations |
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