4252508
Transcription
- What is Transcription?
- A section of DNA is decoded to create
proteins, to create RNA
- A section of DNA is decoded to create
proteins, to create RNA
- Differences from DNA Replication
- Does not use SSB proteins
- Only small section of DNA strand is broken
- The RNA nucelotides have different sugar and uracil replaces thymine
- Also single stranded
- Also single stranded
- No Helicase needed
- Does not use SSB proteins
- What are the sequence of events?
- Elongation
- The RNA Polymerase causes the alpha subunit of ribose
to phosphodiester bond with -OH on the 3rd carbon. A
pyrophosphate is lost
- The RNA polymerase breaks open the RNA strand at -10 box
- The RNA polymerase breaks open the RNA strand at -10 box
- The RNA Polymerase causes the alpha subunit of ribose
to phosphodiester bond with -OH on the 3rd carbon. A
pyrophosphate is lost
- Initiation
- Eukaryotes
- Uses TATA box
- Uses TF's (DABFEH)
- RNA Polymerase II
- Uses TATA box
- Prokaryotes
- Uses -35, -10 and +1 Box
- RNA Polymerase attaches to
the promoter region covering
from -35- +1
- Uses -35, -10 and +1 Box
- Eukaryotes
- Termination
- A terminator region is reached as a result a stem
loop forms. The RNA polymerase gets tangled with
the stem loop and broken off
- They are palindromes and RNA base pair itself
- Factor Row
- After this RNA can go
straight into translatin
- They are palindromes and RNA base pair itself
- Prokaryotes
- Eukaryotes
- Pre-RNA is formed and
further spliced into RNA
- There are three parts to this: Capping,
Polyadenylation and Intron Splicing
- Capping
- Guanine bond joined by 5 - 5 prime tri phosphae
bond on 5 prime end base of the pre-MRNA
- The guanine is then methylated
- The guanine is then methylated
- Guanine bond joined by 5 - 5 prime tri phosphae
bond on 5 prime end base of the pre-MRNA
- Polyadenylation
- Signal reached, cleaved 10-30 bases downstream,
250 adenine bases added
- Signal reached, cleaved 10-30 bases downstream,
250 adenine bases added
- Intron Splicing
- Uses snRNP
- OH on 2 prime carbon nucleophilic
attack on 5 prime end of intron
- The 5 prime -OH attackes 3 prime
intron end of intron and a lariat forms
- The 5 prime -OH attackes 3 prime
intron end of intron and a lariat forms
- OH on 2 prime carbon nucleophilic
attack on 5 prime end of intron
- Uses snRNP
- Capping
- There are three parts to this: Capping,
Polyadenylation and Intron Splicing
- Pre-RNA is formed and
further spliced into RNA
- A terminator region is reached as a result a stem
loop forms. The RNA polymerase gets tangled with
the stem loop and broken off
- Elongation
- Structure of RNA Polymerase
- Made up of five subunits, sigma subunit can
detach to create a four subunit core enzyme
- Sigma subunit tells RNA polymerase
where promoter region starts
- Made up of five subunits, sigma subunit can
detach to create a four subunit core enzyme
