Chapter 12.1-12.2

Central 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