Flashcards in Block 4 Biochem part 1 Deck (185)
who discovered that DNA is the source of heritable info?
who noticed the relationship btw AT and GC?
most common conformation of DNA
dehydrated form of DNA
form of DNA thought to help relieve stress of the helix around a transcription complex
Which enzyme binds the origin of replication in prokaryotes?
how do bacteria regulate DNA replication?
they only make enough DNAA for 1 replication
what unwinds the DNA in prokaryotes?
what breaks the phosphodiester backbones to relieve supercoiling in prokaryotes?
what makes clean breaks through both strands of DNA to unknot it?
Main enzyme that copies DNA in prokaryotes
DNA pol III`
which enzyme in prokaryotes has 3'-->5' exonuclease activity for proofreading?
DNA pol III
what does DNA pol I do?
in prokaryotes, it excises the RNA primer and adds DNA
what is the eukaryotic equivalent of DNA pol I?
Fen-1 nuclease and RNase H
what does DNA ligase do?
in prokaryotes it ensures all phosphodiester bonds are formed
contains primase and initiates DNA synthesis
synthesizes lagging strand (okizaki fragments) Has 3'-->5' exonuclease activity
synthesizes leading strand, has 3'-->5' exonuclease activity
repairs DNA. cannot excise ribonucleotides or proofread
replicates mitochondrial DNA
the hexameric sequence of telomeres is:
which end of a DNA strand does telomerase elongate?
the 3' end
After telomerase elongates a 3' end, ____ puts on a new primer at the end of the 3' telomere, _____ extends fills in the nucleotides, and _____ removes the RNA primer
-DNA pol delta
what nucleosides are often used to inhibit DNA synthesis?
AZT and 2',3' dideoxyinosine
most common base excision repair-
correcting deaminated cytosines
mismatch-directed DNA repair is mediated by ______
Mut proteins work under the assumption that:
the template strand contains the correct base
in E. coli, the template strand is identified by:
methylation of adenine residues
in eukaryotes, the template strand is identified by:
being the "un-nicked strand"