molecular genetics Flashcards
friedrich miescher
discovered DNA in 1989, named it nuklein because it was found in the cells nucleus
walter fleming
introduced chromatin
nuklein and chromatin are the same thing
by the 1900s it was understood chromatin consisted of
DNA and proteins
PAT levene
believed DNA to be too simple to be ‘genetic material’
-protein was more likely, since amino acids are more diverse
hereditary molecule must be able to
-control protein and enzyme production
-self replicate
-adapt
-found in nucleus
conclusion of Griffiths experiment
R strain bacteria had been transformed by S strain bacteria
-denaturing
avery mccarty - mcleods experiment
adaption of griffins experiment that concluded DNA is the molecule that cntrols herditary
DNA
genetic material
-most cells contain 2m of DNA
mRNA
allows protein synthesis to happen in the cytoplasm
3 structures of DNA
1.phosphate group
2.sugar
3.nitrogeneous base
purine
double ring structure
pyramidine
single ring structure
watson crick model of DNA
devloped 3d model of DNA
double helix
2 chains of nucleotides coiled around each other
nucleotides
structural components/building blocks of DNA and RNA
hydrogen bonds
joins bases of chains, easy to break
-important for replication
importance of phosphates
- linking bonds (connect two compounds, stable, made up of phosphates and esters)
2.negatively ionized (after bonding one oxygen stays negative, protection, keeps nucleotides and DNA within membranes)
why are phosphates insoluable
negative charge
semi conservative replication
uses strand of DNA as template to copy two new strands
-half old half new
meselson + stahl experiment
confirmed semi conservative replication to be true, produced light/medium
light - new
medium - old
ori
site of replication, where it starts unwinding
why are there multiple ori
to speed up process of DNA replication
DNA helicase
enzyme that unwinds DNA helix, breaks 4 bonds
single strand binding proteins
prevent DNA from re-annealing
replication fork
region where activity is taking place
DNA polymerase
enzyme replicates nucleotides
what direction does DNA replicate
5’to 3’
DNA strands replicate
semi discontinous
semi discontinous
process half discontinous
leading
continous and faster
lagging
discontinous in pieces
bidirectional replication
replication happens in either direction/end
lagging strand synthesis
DNA polymerase works away from opening helix, leaves a space imbetween primer -gap