RNA processing

the steps required to produce a useable mRNA

what is RNA processing

prokaryotes, the transcripts are ready for translation

which type of cell (prokaryotes or eukaryotes) have no RNA processing necessary

yes, must be processed and transported to cytoplsasm

Do eukaryotes need to be transcribes

1. additon of a 5' cap
2. additon of a poly- A tail at 3'
3. splicing to remove introns

name the 3 steps of RNA processing

RNA processing is at the RNA stage of transcription

RNA processing is at what stage or transcription- translation (DNA, RNA, or Protein)

there is a methylated cap added to the 5' end and growing pre-mRNA strand during transcription

capping

1) promotion of translation \n 2) regulation of export \n 3) prevention of exon nucleus degradation

name the functions of capping

enzymes outside of nucleus that break down nucleic acids (RNA)

what does exonucleus degredation mean

polydenylation

what does Poly-A stand for

occurs after pre-mRNA is cleaved from DNA template strand a secondary enzyme PAP adds a long chain of adenine base

polydenylation

polydenylate polymerase

what does PAP stand for

degradation of RNA transctipt

what does poly-A tail prevent

introns and extrons

eukaryotic genes are a mixture of

expressed segment of the gene, these sequences are transcribed and translated into a protein

extron

an intervening segment of the gene, these sequences are transcribed but NOT translated

intron

spliceosomes

RNA splicing is carried out by \___________

proteins and small RNA fragments

RNA splicing is a mixutre of

responcible for removing intron segments of the RNA transcript and joining the remaining exons together

describe RNA splicing and its functions

a single gene can code for more thatn one different protein, the inclusion or exclusion of exons can change expression

alternative splicing

1) there's a 5' cap \n 2) 5' un-translated region \n 3) protein coding sequence \n 4) 3' un-translated region \n 5) Poly-A tail

what's left post processing

un-translated region

what does UTR stand for

during transcription

when is the methylated cap added onto the RNA strand

the methylated cap allows it to leave

how can the RNA leave the nucleus

the 3' end

where is the poly-A tail added on

a single gene can code for mote than one protein. the amount of exons included can change the expression of the gene (called alternative splicing)

why are introns important ot have even though they are taken out

recognizes intron segments, cuts them, reconnects exons together

what is the spliceosomes role in RNA splicing