Studied by 3 peopleCentral dogma
proposed by crick, method of DNA transformation into polypeptides
what are polypeptides made of
amino acids
does the central dogma always hold true
no, reverse transcriptase converts RNA back to DNA
what other functional products are produced in transcription besides proteins
mRNA and rRNA
are rRNA and tRNA translated into polypeptides?
no, the only molecule that is translated into a polypeptide is mRNA
transcriptional unit
sequence of DNA that codes for a single RNA molecule, including sequences necessary for its transcription
where does the RNA polymerase bind in replication
to the promoter region
what direction does RNA polymerase go in?
5’ to 3’
what organism co transcribes genes
bacteria, prokaryotes
operon
forms in the co transcription of genes, genes that are linked together
what are the three stages of transcription
initiation, elongation and termination
initiation
transcription factor binds to promoter and recruits RNA polymerase
elongation
DNA strands separated and RNA polymerase synthesizes RNA strand
termination
terminator sequences causes dissociation of RNA polymerase and completed RNA
transcriptional start site
labeled as +1, refers to the 1st nucleotide used as a template for transcription
where are number labels given on the DNA
to the top strand, ( template strand) only
does spacing between the -10 and -35 regions matter for promoter functionality
yes
how many subunits does the core RNA polymerase have
5
holoenzyme
the core RNA polymerase joined with the sigma factor, binds to the promoter and is associated w/ RNA polymerase
what bonds are between the sigma factor and the promoter
hydrogen, non covalent bonds
does elongation occur with the RNA polymerase or holoenzyme
RNA polymerase
does bacteria have single or multiple sigma factors
multiple
consensus sequence
most common sequence recognized by a sigma factor
template strand
used by RNA to build off of, complementary to RNA, upper strand of DNA
coding strand
same as RNA, except uracil replaces thymine
what strand does the sigma factor bind to
the coding strand
what are the two termination mechanisms of bacterial transcription
rho dependent termination, rho independent termination
what is the recognition site in rho dependent termination
rho utilization site, p protein binds here
p protein
type of helicase separating the RNA-DNA hybrid in the open complex
termination site in rho dependent
contains a stem loop which binds to RNA pol, changing its conformation causing it to pause, p protein catches up and helicase activity breaks H-bonds between RNA-DNA complex
rho independent termination
doesn’t require p protein, sequence contains a stem loop and a sequence rich in uracil
Note
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