Introduction to Bio 2 Flashcards
How do DNA strands run
antiparallel
DNA theories
semiconservative = strands unwound and each daughter has one new and one old conservative = strands unwound and one completely new one is made and the original Dispersive = strands are used alternatively
Whats the main evidence for these models
1958: Mathew meselson and Frank Stahls experiment
Whats the replication rate
2 kb/minute, initiates at many different sites simultaneously
growing strand is in what direction
5 to 3
Where are phosphate groups bound
the 5 end hydroxyl group of nucleotide attacks 3 hydroxy group at end of the chain
Lagging strand
synthesised in short fragments
RNA primer required
Where is DNA primase found
animals cells
Where is RNA primase
in bacteria
Whats the role of telomerase
provides a mechanism to extend the template until its long enough for normal lagging strand synthesis
What is the genetic sequence for telomeres
TTAGGG
Where are telomeres active
in stem cells and actively proliferating cells
less active in somatic cells - ageing
When are errors removed
during synthesis
mutations can also be removed post-replicatively
What percentage of mistakes are caught by proofreading exonuclease associated with polymerase
99.9%
What is the overall mutation rate
10^10
1 error every 3 genomes replicated
