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Micro, genetics


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translation begins with
protein synthesis
expressed properties such as eye color and curly hair is called
3 types RNA

(There is no uRNA)
RNA polymerase is
an enzyme used in the synthesis of RNA
The promoter site is
the site where RNA polymerase binds to DNA
mRNA language consists of
three nucleotides called codons
repressors function to
stop the initiation of transcription
an operon consists of
structural genes, regulatory genes, and control genes
what factors affect a culture media
nutrients, moisture, pH, oxygen, sterile (no living microbes) temperature
chemically defined media
exact chemical composition not known
complex media
varies from batch to batch, Ex nutrient both and nutrient agar
anaerobic culture media
reducing media that contains chemicals that combine w free oxygen.
selective media
supresses unwanted microbes and encourages desired microbes- has specific growth requirements
differential media
makes it easy to distinguish colonies of microbes
enrichment media
encourages growth of desired microbe
streak plate
pure culture (only one species or strain)
prokaryote reproduction
binary fission, budding, conidospores, fragmentation of filaments
growth phases are:
lag, log, stationary, death
measuring microbial growth-direct methods
plate count, filtration, MPN, direct microscopic count, dry weight
measuring microbial growth- indirect methods
turbidity, metabolic activity, dry weight
passage of liquid or gas through a material. Filtration removes most bacteria
disadvantage to direct microscopic count
not accurate, counts living and dead cells, requires lots of cells
bacterial contamination
no contamination
removal of all life
counter top
used on living tissue
removal germs from limited area
lower microbial counts, (eating utensils)
cide = kills
inhibits furthur bacteria from growing
microbial death
bacterial populations die at a constant lagarithmic rate
effectiveness of antimicrobial treatment depends on
# microbes, environment, time of exposure, microbial characteristics
actions of microbial control agents
alteration to plasma membrane permeability, damage to proteins/enzymes, damage to nucleic acids (DNA/RNA)
Physical methods of microbe control
moist heat, autoclave (kills all but prions), steam (must contact items surface), home canning (pressure cooker, air removal), pasteurization (*reduces* spoilage),
thermoduric organisms
are heat resistant
Dry heat sterilization kills by
oxidation (flaming, incineration, hot-air sterilization.)
HEPA filter
removes microbes from the air
dessication prevents
metabolism. Drys out, removes water. (freeze dried coffee)
radiation damages
DNA (hydroxyl radicals). Ex. x-ray, gamma ray, electron beams
kill by heat, not especially antimicrobial
Chemical methods disinfectant-principles of effectiveness
1- concentration of disinfectant, organic matter, pH, time
evaluating a disinfectant
use dilution test, use disk diffusion test
DNA is copied by
DNA polymerase in the 5'3' direction, initiated by RNA primer
synthesizing RNA from DNA template. DNA is transcribed to make RNA
Transcription begins when
RNA polymerase binds to promoter sequence
Transcription proceeds in the _____ direction
5' to 3'
transcription stops when
it reaches the terminater sequence
mRNA puts_______ to DNA molecule
complementary base pairs
mRNA exits the _____ and enters the _______ to be made into a protein
nucleus, cytoplasm
mRNA is tranlated in codons (3 nucleotides)
translation of mRNA begins at the _______
start codon AUG
translation ends at the _______
stop codon UAA,UAG, UGA
u are awful, u are gross, u go away
tRNA recognizes _______
tRNA contains
amino acid, anticodn and complex protein
2 Types of Mutation
base substitution and frameshift
spontaneuous mutations occue int the absence of
agent that cuases mutation
degenerate genetic code
3rd base of codon is different
Mutation--base substitution is called a ________
point mutation.
missense (mistake) change in one base, result in change of amino acid
nonsense codons
stop codons

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