Lecture Nov 25 (DNA Replication pt 1) Flashcards
How is cAMP made?
cyclic AMP, made from ATP.
Enzyme gets rid of 2 phosphates on ATP
DNA Replication
How does DNA replication start in Ecoli? What sequence does DNA-A bind to in replication?
DNA-A binds to E.coli OriC
TTATCCACA (happens 4 times) and AT rich region
What makes up the OriC?
the TTATCCACA (x4) and AT rich region.
In DNA Replication, how does initiation occur?
- DNA A binds to TTATCCACA sequence and opens up DNA at AT-rich sequence
- DNA B is opened up by DNA C and attached to the DNA strand
- DNA G (primase) binds to DNA B
- DNA C dissasociates and DnaB starts to move down ssDNA in 5’ to 3’ direction
What does DNA B do?
The helicase
What does DnaC do?
Helicase loader
Puts DNA B on to DNA. Opens DNA B so that it can insert the DNA strand
Note: DNA B cant move unless DNA C is off
What does DNA G do?
Puts down RNA primers
What direction does DNAB move?
towards 3’ (5’ to 3’)
Is DNAB attached to lagging or leading strand?
Lagging
What is a replisome
like large unit of all the parts involved in replication
Parts of the replisome
- DnaB
- DnaG
- DNA polymerase III
- β-clamp
- clamp loader
- SSB
- template DNA and RNA primer
Parts of DNA Polymerase 3
ATE!!
Alpha
Theta
Epsilon
What does the theta subunit of DNA Polymerase 3 do?
Stimulates the epsilon subunit
What does the epsilon subunit do?
3’ to 5’ exonuclease, removes nucleotides
in 3’ to 5’ direction, used for proofreading
What does the alpha subunit do?
5’ to 3’ polymerase, the major catalytic
function of a DNA polymerase
What does the Beta clamp do?
Binds to the ssDNA AND β-clamp locates behind DNA polymerase III
2 types of transcription factors?
Transcription activators and repressors
What is positive regulation
When a transcription activator helps increase the rate of transcription
What id negative regulation
When a transcription repressor is used
Whats the difference between glucose and galactose?
Both have the same chemical formula, but galactose has OH group on 4th carbon pointing up
What is the purpose of cAMP?
Binds to CAP so that it can bind to the DNA and let RNA polymerase transcribe
