Bacterial DNA replication and partitioning Flashcards
what are the following abbreviations
bp
kb
Mb
Gb
base pair
1000 bp
1,000,000 bp
1,000,000,000 bp
How big is human genome
3 Gb
How big is bacterial genome
08-13 Mb
what is horizontal gene transfer
happens when genetic information is passed sideways from a donor to an unrelated organisms
usually involves plasmids, viruses, or transposons
What is e coli? Gram + or Gram -
Gram -
Bacterial nucleoid
fileld with bacteria chromosomes
where are ribosomes and transcription machinery in bacteria?
the outside fo the nucleoid because of their size
What two levels of compaction are essential to chromosome
supercoiled and folded into ~30 ~300 topologically isolated domains that are arranged around a protein scaffold
are nucleoid placements random?
no, they are positioned specifically
where are highly transcribed genes located
the periphery of the nucleoid
what bends DNA
What is supercoied?
DNA negatively supercoiled
what is the form of DNA
right handed super helix
what does negative supercoiling do?
underwinds it and facilitates the formation of bubbles
What does positive supercoiling do?
overwinds
Topoisomerave IV does what
works behind the replication form and untangles the newly formed DNA as replication proceeds
what is OriC
DNA replication stats at this cite and proceeds in both directions around the circle
What enzymes are important in bacteria replication
DnaA, DnsB, DnaC, DNA gyrase, SSB
Hemimethylated
the old strand is methylated but the new strand has not yet been methylated
what happen if hemimethylated
can not replicate again???????
what does asymetric distribution of DNA do?
aids in the organization and segregation of the genome
what does Tus do?
binds symmetrically and stops the movement of the form from one direction only
what is a septum?
a cross wall between two daughter ceolls
what is partitioning?
segregation
