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