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Review Definitions

Terms in this set (46)

antimicrobial modes of action
alteration of cellular membrane permeability, damage to cellular proteins (enzymes), damage to microbial nucleic acids
Sterilization
elimination of all microbial life (including endospores)
methods of sterilization
moist heat (autoclave), dry heat, radiation, filtration, gas
pasteurization
moderate heat, eliminates pathogens/reduces numbers
examples of ionizing radiation
gamma rays, x-rays, electron beams
ionizing radiation
short wavelength, high Energy, high penetration, lethality due to generation of free radicals which damage DNA
nonionizing radiation
longer wavelength, low Energy, low penetration, lethality due to generation of thymine dimers (inhibit DNA replication)
examples of nonionizing radiation
UV light
gram negative
bacteria more resistant than gram positive due to liposaccharide layer
pseudomonas
very resistant to antimicrobials due to porins in their cell walls
microbial control in the kitchen
avoid cross contamination of foods eaten raw with food requiring cooking
microbial control in the hospital
extra precautions are necessary due to increased susceptibility of patients (open wounds, immunosuppression, increased exposure to pathogens)
genome
the genetic information in a cell
chromosomes
structures containing DNA
genes
segments of DNA that encode proteins
DNA
macromolecule composed of repeating units called nucleotides, each consisting of a nitrogenous base, deoxyribose, and phosphate group
complimentary DNA strands
specific base pairing between opposing strands of dsDNA
A
T
G
C
genetic alphabet
gene products are determined by nucleotide sequence which comprise the 4-letter alphabet
genotype
the genetic makeup of an organism (the potential, but not the actual properties, an organism's collection of genes)
phenotype
the actual properties of an organism (the expression of the genotype, an organism's collection of proteins)
transcription
synthesis of C' strand of mRNA (a transcript) from a DNA template
translation
conversion of the information contained in the mRNA transcript into proteins (tRNA reads the mRNA code and delivers appropriate amino acids for protein synthesis)
mutations
changes in the base sequence of DNA, the effect of which may be: silent/neutral, detrimental, or beneficial
vertical gene transfer
passage of genetic information from one generation to the next (from parent to offspring), occurs in all organisms
horizontal gene transfer
passage of genetic information laterally, to members of the same generation (bacteria)
transformation
transfer of "naked" DNA
conjugation
transfer of plasmids; requires direct contact
transduction
transfer of DNA by a virus
transposition
a specialized form of transfer involving transposons- cannot be transferred directly
causes of antibiotic resistance
antibiotic overuse and misuse, people ask for them when they don't need them, doctors proscribe them when they don't need to
natural selection
in nature, organisms with beneficial traits replace organisms lacking those traits
artificial selection
used by humans to select cultivatable organisms with beneficial traits
improved medical products/techniques
pharmaceuticals, vaccines, gene therapy
scientific applications
rDNA technology allows amplification and analysis of DNA- DNA sequencing, genetic screening, diagnostic/forensic medicine
agricultural applications of genetic engineering
improvements in both animal production and plant production
biotechnology concerns
production of recombinant organisms with adverse traits; accidental release/spread of rDNA or genetically-altered microbes
biotechnology precautions
deletion of essential genes, insertion of suicide genes with delayed expression
genetic engineering of plants
using the Ti-plasmid from Agrobacterium and a natural insecticide gene isolated from another organism, recombinant plants have been produced which are resistant to insects
traditional vaccines
despite numerous successes they have some problems
genetically-engineered vaccines
rDNA techniques can be used to produce large quantities of microbial antigens, result is safer, yet effective subunit vaccine that does not require cultivation of the pathogen
molecular (cDNA) probes
ssDNA fragments C' to nucleotide sequence of gene/genome you wish to detect; very sensitive; carry a tag to detect binding to target DNA
eukarya
plants, animals, fungi, protists
bacteria
prokaryotes that typically contain peptidoglycan in their cell wall
archaea
prokaryotes lacking peptidoglycan in their cell walls (ancient organisms, often found in extreme environments)
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