Chapter 18 Flashcards
operator
the on off switch when metabolic pathways are being synthesized
operon
the operator, the promoter, and the genes they control
repressor
protein that can turn an operon off, prevents gene transcription by binding to the operator and blocking RNA polymerase
regulatory gene
gene that creates the repressor
corepressor
molecule that cooperates with a repressor protein to switch an operon off
inducer
inactivates the repressor
lac operon
inducible operon and contains genes that code for enzymes used in the hydrolysis and metabolism of lactose
cyclic AMP (cAMP)
activates CAP, accumulates when glucose is scarce, and activator
activator
protein that binds to DNA and stimulates transcription of a gene
negative gene regulation
ex. trp, the process of regulating gene expression by inhibiting the expression of that specific gene
positive gene regulation
the binding of specific protein is required for transcription to begin, ex. lac operon process
differential gene expression
the expression of different genes by cells with the same genome
histone acetylation
the addition of an acetyle group to an amino acid in a histone tail
DNA methylation
a different set of enzymes can methylate the DNA itself on certain bases, usually cytosine
epigenetic inheritance
inheritance of traits transmitted by mechanisms not involving the nucleotide sequence itself
control elements
segments of noncoding DNA that serve as binding sites for the proteins called transcription factors
enhancers
the more distant distal control elements
alternative RNA splicing
different mRNA molecules are produced from the same primary transcript
proteasomes
giant protein complexes that bind protein molecules and degrade them
MicroRNAs
small single stranded RNA molecules that can bind to complementary mRNA sequences, can degrade or block mrna
Small interfering RNA
similar to miRNA and associate with the same proteins
RNA interference
used as a means of disabling a specific gene to investigate their function
non protein coding DNA
corresponds to the portions of an organisms genome that do not code for amino acids
non coding RNA
a functional RNA molecule that is not translated into a protein
