eukaryotic polymerases

Question 1

what are the main steps of eukaryotic translation?

Answer 1

binding
initiation
elongation
termination

Question 2

which part of transcription process does most regulation occur?
A binding
B initiation
C elongation
D termination

Answer 2

A and B

Question 3

what is the mitch polymerase called? What does it do?

Answer 3

mRNAP or POLMRT able to transcribe 3 polycistronic transcripts

mRNAP polypeptide is encoded on chr 19

Question 4

how does mRNAP relate to evolution?

Answer 4

as mitch derive from bacterial endosymbiosis, this single polypeptide is structurally similar to bacteriophages

Question 5

what is the purpose of promoters?

Answer 5

cis-acting elements and help with orientation and binding of RNA polymerase

for transcriptional initiation

Question 6

why does mRNAP require additional factors like TFAM, TEFM, MTERF?

Answer 6

need them to recognise the binding sites and hekps with transitions of differennt steps of transcription

Question 7

how do the accessory factors for mRNAP help with transcription?
> structurally

Answer 7

when transcription elongation complex forms, the a-factors convert mRNAP into a processive polymerase

able to continously carry out DNA synthesis without pausing/frequent dissociation from template

Question 8

what is the function of terminator sequence?

Answer 8

allows RNAP to stop transcribing and dissociate from DNA and release RNA transcript

= transcription is terminated

Question 9

what are the main differences between euk mRNAP and nuclearRNAP?

Answer 9

nRNAP employ 100 a-factors whilst mRNAP use 4

nRNAP transcribes 22,000 transcripts, mRNAP does 3 transcripts

Question 10

what is a unique feature of RNAP-2? What is its purpose?

Answer 10

has a reversibly phosphorylated CTD. Unphosphorylated, able to be recognised by general TF

phosphorylated by TFIIH allowing GTF to dissociate and elongation factors bind = TEC formation
also binding of termination factors

Question 11

where does transcription take place in euk and pro

Answer 11

pro - in the nucleus alongside translation

euk - in the nucleus alonqgside the rna processing

Question 12

what is a feature of RNAPII promoters?

Answer 12

if it is a housekeeping gene, often promoter contain a CpG island

also promoters are highly variable and diverse with many motifs, not just TATA box

Question 13

what do the 3 RNAP nuclear trancribe?

Answer 13

RNAP1 = rRNA
RNAP2 = mRNA
RNAP3 = tRNA

Question 14

how does the mechanism of transcription using RNAP-3 differ from usual?

Answer 14

because of its small size, no need for elongation factors and also able to terminate too

> RNAP-3 is self sufficient and
doesn’t require accessory factors

Question 15

how does RNA polymerase move along the DNA?

Answer 15

by scrunching, inchworming or transient excursions (move and pause)

Question 16

what are enhancers?

Answer 16

they are long-range regulatory elements found upstream of the TRANSCRIPTION START SITE

able to recruit mediator complex which activates and finetunes transcription, aids helicase and kinase activity of TFIIH and K

Question 17

what are the different classes of TF structure?

Answer 17

helix -turn helix
zinc finger
basic leucine zipper
basic helix turn helix

Question 18

how does histone and dna interact?

Answer 18

histone is 147bp protein made up of H1 linker, h2a, H2b H3, H4 OCTAMER

dna will wrap around histone 1.7 times and helps to stabilise and package DNA as histones are postively charged aa and dna phosphates are neg-

Question 19

what is the functions of chromatin remodelling complex?

Answer 19

MULTIPROTEIN COMPLEX that can modify histones by sliding or detaching// uses protein binding to create nucleosome free zones or even encourage nucelosome formation

or can post-transcriptionally modify histone tails
> basis of epigentic