what are 4 differences between prokaryotic and eukaryotic transcription
- no nucleus in prokaryotes
- eukaryotes have a more complicated process
- they differ in organization of DNA
- in eukaryotes, transcription and translation are separate, whereas they occur at the same times in prokaryotes
how is gene expression controlled in eukaryotes?
by three RNA polymerases
what do General Transcription Factors do?
they are involved in an elaborate process of recognition of promoter elements and assembly of a pr-initiation complex, they then load the RNA polymerase
what are enhancers?
regulatory elements that work from great distances
what is the primary purpose of gene control in multicellular organisms?
the execution of precise developmental and tissue-specific programs so that the proper genes are expressed in the proper cells at the proper times
where does transcription take place in eukaryotes?
on DNA that is wrapped in chromatin
why does chromatin go from the closed, condensed form to open form?
chromatin needs to be open for a gene to be activated and for transcription to proceed
heterochromatin
- regions of chromosomes that are densely packed
- rich in repetitive DNA such as transposons, centromeres, telomeres
- not accessible to transcriptional machinery
- inactive genes are found in heterochromatin
euchromatin
- less dense regions of chromatin
- active genes are found euchromatin
