Replication/Transcription/Translation Flashcards
DNA polymerase
has subunits on core enzyme
Alpha, epsilon, theta
what does alpha do on DNA Pol
machinery, polymerase
what does epsilon do in DNA Pol
exonuclease activity (proof reading)
what is role of theta subunit
activates exonuclease activity/proof reading
DNAb
aka helicase
breaks H bonds of DNA and separates strand
promotes primase activity
SSB
bind single stranded DNA after strands are separated by helicases
Topoisomerase
separation of chromosomes upon completion of DNA replication
relieves tension
Primase
synthesis of RNA primer
Gyrase
relieves supercoiling of DNA produces as DNA strands, separated by hellicases
separates daughter molecules in final stages of replication
Abs target
DnaC
helices loader, directs DnaB to template
ribonuclease H (RNA-H)
removes RNA primers
DNA ligase
seals together nicked DNA, joining fragments together
Tus
terminates replication
What part of RNA Pol factor has no catalytic activity but aids in transcription initiation?
sigma
sigma factors transcription
initiation of transcription
binds to DNA at promotor region at -10 sequence and -35 sequence
-35 sequence
RNA Pol recognition site
-10 sequence
RNA Pol binding site
pribnow box
TATAAT
what makes up the holoenzyme
core enzyme + sigma factor
Rho is active in which process
termination of transcription
pressure on DNA/RNA hybrid that stimulates it release
rho independent pathway
pausing at termination site (UA rich regions) that forms a loop structure which destabilizes UA bonds and pulls apart DNA/RNA hybrid
rho dependent pathway
binding of Rho at rho entry site
travels mRNA to “catch up” with RNA Pol then grabs it when RNA Pol pauses to destabilize RNA/DNA hybrid, stimulating separation
-10 and -35 regions are found in what region
promotor
leader sequence
transcribed but since it is upstream of the starter, it is not translated
has shine delgarno sequence – binding of 16s
23s catalyzes…
formation of peptide bond between newly synthesized proteins
translation initiation
- initator codon binds 16s rRNA in 30s subunit
- Shine delgarno sequence is aligned with 16s rRNA
- IF-3 binds to 30s, prevents it from binding to 50s
- IF-2 binds to GTP, mRNA, tRNA and guides to P site of 30s
- IF-1 binds to 30s, removes IF-3, 30s binds to 50s
- GTP hydrolyzes, IF-1, IF-2 removed and 70s initiation complex is formed
is RNA transcribed one at a time?
no, you can have multiple ribosomes transcribed/bound to rRNA
polyribosome
what are differences between eukaryotic and prokaryotes
introns and exons in eukaryotes
polysystronic mRNA in prokaryotes
polysystronic mRNA
prokaryotes
allows translation of a single RNA but lots of proteins produce
stop codon
doesn’t code for an AA, they instead catalyze a reaction that produces water
release factors
termination
cause ribosomal subunits to come apart and release
protein splicing
Removal of part of polypeptide before folding
Inteins – removed portion
Externs – portions that remain in protein
some bacterial peptides, right after translation but before final folding conformation
