W8 Transcription Flashcards
what are the 2 regulatory elements
promotors and enhancers
which direction are promotors
proximal
which direction are enhancer
distal
what are found on promotors
transcription factor binding sites
what section of genes are transcribed but then spliced out
introns
where is energy for transcription from
hydrolysis of the ribonucleoside
triphosphate
what type of polymerase do eukaryotes use
RNA polymerase 2
what does RNA polymerase 2 do
- Unwinds DNA
- form phosphodiester bonds
- Proof-reading and correction
why are DNA and RNA polymerase diff
Processivity
how does bacteria transcription occur
- sigma factors take RNA polymerase to specific promotor
- RNA polymerase binds to promotor seq
- forming a closed complex
- DNA is unzipped and opens the complex to form a transcription bubble
- RNA polymerase will elongate by placing RNA nucleotides
describe 5’ capping
- adds a m7G cap to mRNA
- guanyl transferase adds the G
- methyl transferase add the methyl group
what is a promotor
a region of a gene that polymerase binds to for downstream transcription
how do eukaryotes initiate transcription
- enhancers will interact with transcription binding proteins via a mediator
- RNA polymerase will elongate after binding to a transcription factor
why is the mRNA strand and coding strand the same
both complementary to template strand
how can you tell a cell is prokaryotic
- transcription and translation happening simultaneously
- contains introns
what is the 5’ cap called
m7G cap
how does the m7G cap bind to mRNA
5’ to 5’ triphosphate bridge
why is 5’ capping needed
to allow for exports and translation to begin
describe how splicing works
- branch point protein finds adenine in intron
- takes the 2’ OH group and binds to the A on the intron
- unstable to creates a lariat loop complex
- exon junction complex forms after intron is removed
how do you stop eukaryotic transcription
- use cleavage stimulation factor (CstF)
- cleavage sequences
- 3’ polyadenylation creates an A tail at the end of the transcript
how can RNA be sequenced
NGS
how are gene functions studied
gene ontology
what’s a way to detect the diff between DNA and RNA
RNA has a 2’ OH group but DNA doesn’t
what is the role of a spliceosome
holds regions of splicing in place
what are spliceosomes made of
snRNAs form complexes with proteins
what’s the job of snRNAs in splicing
find splice sites and catalyse reactions
what is alt splicing
can sometimes cut introns/exons
what is transcriptomics
reads how much a gene is expressed
