test 2 terms Flashcards
operon
functioning unit of genomic DNA containing cluster of genes under control of a single promoter
mutation
change in genetic material permanent change in the base of sequence or DNA, could be beneficial or harmful
genotype
genes or genetic makeup of an organisms, all the DNA
phenotype
expression of genes, what we see
constitutive genes
genes that are expressed all of the time, genes that are always being produced (ribosome)
transposons
small segments of DNA that can move from one region of DNA molecule to another, can leap from one chromosome to another
transformation
genes are transferred from one bacterium to another as “naked” DNA in a solution
gene
a segment of DNA encoding a functional product
mutagen
agent that causes mutations
codons
sequence of three nucleotides that specifies the insertion of a specific amino acid
inducible genes
initiates transcription; “off” mode, turned on by environment inducer
repressible genes
inhibits gene expression; “on” mode, turned off by environmental compressor and repressor
sepsis
refers to microbial contamination
autoclave
steam under pressure with high heat, equipment used for sterilization by steam
psychrotrophs
grow between 0C and 20-30C, cause food spoilage
biofilms
microbial communities, form slime or hydrogels, share nutrients, sheltered from harmful factors
lypophilization
freeze dry- frozen and dehydrated in a vacuum, -54C to -72C
generation time
time required for a cell or population to double in number
colony forming unit
visible bacterial colonies on solid media, one singular colony
bacterial colony
population of cells arising from a single cell or spore or from a group of attached cells
selective media
suppress unwanted microbes and encourage desired microbes
reducing media
contain chemicals that combine with dissolved O2 and deplete the O2 in that medium
