gel made of a polymer as a sieve to separate a mixture of nucleic acid fragments by length

enzymes that cut DNA molecules at a limited number of specific locations

protect bacterial cell by cutting up foreign DNA from other organisms or phages

created from restriction enzymes cleaving sugar phosphate backbones in the 2 DNA strands in a staggered manner

first step is to obtain a plasmid (originally isolated from a bacterial cell and genetically engineered for efficient cloning)

a molecule containing DNA from 2 different sources, often different species

after process is complete, the plasmid can be turned back into a bacterial cell, called a recombinant bacterium

turns sample sets of mRNAs into double stranded DNAs with corresponding sequences

resulting double stranded DNA called complimentary DNA (cDNA)

allows a cell to adapt to short term fluctuations in the supply of a substance it needs

when the product of a reaction shuts down the reaction, product is the inhibitor

cells can adjust the production of certain enzymes, can relate the expression of genes encoding the enzymes

positioned within promotor or between promoter and enzyme coding genes

binds to operator and blocks attachment if RNA polymerase to the promoter

small molecule that cooperates with a repressor portion to switch an operon off

protein that binds to DNA and stimulates transcription of a gene

means that RNA polymerase can bind to the promoter and transcribe regions of the gene

when tryptophan binds to trp repressor at an allosteric site the repressor protein changes to the active form to sttscth to the operator, turn the operon off

inducible operon because it is usually off but can be stimulated into transcription

repressible operon because its transcription is usually on but can be inhibited

gene for β-galactose (lacZ) is part of lac operon which includes 2 other genes for coding enzymes that function in the use of lactose

entire transcription unit is under the command of one main opener and promoter

codes for allosteric repressor protein that can switch off the lac operon by binding to the operator

inactive by itself, needs tryptophan as corepressor in order to bund to operator

chemical modifications to histone can influence protein structure and gene expression

chromatin modifications do not change DNA sequence, but they can still be passed down to daughter cells

high levels of transcription in specific proteins depend on specific factors

activator proteins -> DNA binding domain & activation domains

facilitates series of protein-protein interactions, results in enhanced transcription