RNA and transcription units

genetics - RNA and transcription units

mRNA

directs the synthesis of proteins

proteins

source of mRNA determines the identity of newly made ____

leader, coding, and trailer

the 3 sequences that make of the structure of mRNA

leader sequence

sequence that makes up mRNA that is important for initiating protein synthesis

coding sequence

sequence that makes up mRNA that has the longest area and holds the nucleotides that encode the amino acid sequence

trailer sequence

sequence that makes up mRNA that is after the end of synthesis and regulates the lifespan of the mRNA

heteronuclear RNA

hnRNA

hnRNA

the precursor to mRNA

capping

process of adding specialized guanosine residue to the 5’ end of RNA, this aids in the initiation of protein synthesis

protects 5’ end from exonuclease

how does capping aid in the initiation of protein synthesis?

7-methyl-guanosine

specialized guanosine residue added to the 5’ end of RNA

exonuclease

enzyme that chews the ends of the DNA strand

enzyme that chews the middle of the DNA strand

tailing

process of adding a string of As (25-200) to the 3’ end of RNA: the Poly-A tail, defines the lifespan of the mRNA

splicing

process of cutting out portions of RNA and piecing together the remaining portions to be exported into the cytoplasm

larger

pre-mRNA inside the nucleus is ____ than mRNA in cytoplasm

introns

removed during splicing; non-coding sequence

exons

pieced together during splicing; the coding sequence

promoter, transcribed region, terminator

What are the 3 parts of the DNA sequence needed for synthesis?

promoter

one of the transcription units, has a 5’ sequence, is the site where RNA pol is loaded onto DNA, the site of transcription initiation, has regulatory elements

transcribed region

one of the transcription units where RNA pol uses ssDNA as template, the site of elongation

terminator

one of the transcription units, has 3’ sequence, is the site where RNA pol is dislodged from DNA, and the site of ending transcription

capping of mRNA

what doe sthis image show? 

binds promotor to recruit RNA pol

what is the purpose of the sigma factor in this diagram? 

cause RNA pol to release RNA strand

what is the function of rho in this image? 

terminate transcription by removing RNA pol

what is the function of the hairpin structure?

transcription factors

what is this image showing? 

multiple copies of rRNA genes being transcribed

what is this image showing? 

ribosome

what is this image showing? 

-35s, Is, -10s, Is

what is the order of the 4 different sequences in a bacterial promotor?

prinbow box

what is the other name for the -10 sequence in a bacterial promotor? this functions as one of the binding sites for RNA polymerase to initiate transcription

-35s and -10s

what are the 2 binding sites for RNA polymerase in bacteria?

16-19

The first intervening sequence (Is) in bacteria is how many base pairs long?

6-9

the second intervening sequence (Is) in bacteria is how many base pairs long?

RNA start site

what comes after the second intervening sequence in a bacterial promotor?

length

what about the intervening sequence must stay the same for regular transcription to occur?

sigma factor

binds promotor and recruits RNA polymerase

released from promotor

what happens to the sigma factor after RNA polymerase begins transcription?

helicase

what type of enzyme is rho?

mRNA

rho binds ____, moves 5’ → 3’

rho dependent termination

type of termination where something catches up to polymerase, finds RNA:DNA hybrid, and disrupts it?

rho independent termination

type of termination that uses inverted repeats in sequence of terminator to dislodge RNA pol

AT-rich region

what usually follows inverted repeats?

hairpin structure

what structure is created by inverted repeats in the nucleotide pattern?

3

eukaryotic promotors have ____ different classes

enhancers

regions of DNA distant from promotor that regulate level of expression ot promotor

distance and position

enhancers are ____ and ____ independent

basal factors, activators, coactivators, repressors

what are the 4 types of regulatory proteins in eukaryotes?

basal factors

one of the 4 regulatory proteins in eukaryotes; similar to transcription factors, proteins that bind promotor and recruit RNA pol

activators

one of the 4 regulatory proteins in eukaryotes; bind enhancers and stabilize transcription factors

coactivators

one of the 4 regulatory proteins in eukaryotes; assist the activators, not DNA binding proteins

repressors

one of the 4 regulatory proteins in eukaryotes; bind silencers and prevent activators from binding