DNA Transcription Flashcards
What are the different types of genes
Structural
Temporal
Positional
Inducible
When were genes first connected to enzymes
Archibald Garrod noticed that the disease alkaptonuria was inherited from a recessive allele. He proposed that patients with the disease lack a particular enzyme.
What was the Beadle and Tatum experiment
They deliberately created mutations in chromosomes to verify whether they acted in an Mendelian fashion. There results led to the one gene one enzyme hypothesis.
What does ex novo mean
A primer is not required
RNA can be synthesised ex novo during transcription
What direction does transcription occur in
5’ to 3’
How many subunits make up RNA polymerase
5
5 core subunits: a2, b, b’, w
1 other subunit: o (sigma): this is not usually considered a subunit
How are transcription units numbered
Preceding the initiation site: upstream, has negative numbering
After the initiation site: downstream, has positive numbering
What are the regions of a promoter
Start point (+1)
Consensus sequence (-10)
Spacer
Consensus sequence (-35)
The upstream element or UP (-40 to -60 consensus sequence)
What is the Rho factor
A homohexameric complex (six identical subunits)
It binds to RNA and has ATPass and helicase activity
What is rho dependant termination
rho binds to the RNA strand
It chases RNA polymerase down the strand (hot pursuit model)
It scans the RNA for a termination site
Once the site is found, it acts as a helicase and unwinds the RNA from the DNA template strand
What is DNA footprinting
A way to find a protein-nucleic acid binding site
DNA bound by a protein will be protected from chemical cleavage at its binding site
How does DNA footprinting work
Isolate the DNA thought to have a binding site
Radiolable the DNA
Bind the protein to the DNA
Cleave the DNA with an enzyme of chemical agent
Electrophoreses to separate product and then view via X-Ray
