`Chapter 11 Genetic analysis
dsDNA: double strand DNA
Fidelity: accuracy of the process
Conservative model: 1 new DNA 1 old DNA (both parental strands stay together)
Semiconservative model: 2, 1 parental strand, 1 daughter strand
Dispersive model: parental and daughter strand are interspersed
ON EXAM: For example: Percentage of mixed bands after 8 generations (DRAW!!!)
15N (heavier) -> lighter 14N added -> bands go from heavy to half heavy -> bands go to half
heavy/light -> Semiconservative model
Bacterial DNA replication:
1 origin of replication in both ways (bidirectional)
oriC: origin of Chromosomal replication
- AT- rich region (easier to break hydrogen bonds)
- DnaA boxes
- GATC methylation sites
-> DnaA proteins bind to DnaA boxes
-> DnaA proteins recruit other proteins
-> DNA bends
-> AT-rich region separates
-> DNA helicase: breaks the hydrogen bonds between the DNA strands.
Dam (DNA adenine methyltransferase): methylates adenine
Newly replicated DNA/daughter strand GATC is not methylated
DNA needs to be methylated before replication can start again
Summary enzymes:
-DNA helicase: breaks the hydrogen bonds between the DNA strands.
-Topoisomerase II: alleviates positive supercoiling. (DNA gyrase)
-Single-strand binding proteins: keep the parental strands apart.
-Primase: synthesizes an RNA primer.
-DNA polymerase I: removes the RNA primers and fills in with DNA
-DNA polymerase III: synthesizes a daughter strand of DNA.
-DNA ligase: covalently links the Okazaki fragments together.
DNA polymerase
-DNA polymerase I: removes the RNA primers and fills in with DNA
-DNA polymerase III: sigma subunit synthesizes a daughter strand of DNA
Sigma subunit + 9 subunits = holoenzyme
Processive enzyme: an enzyme, which glides along the template strand and does not
dissociate from it while catalyzing attachment of nucleotides.
Proofreading function: ability to remove mismatched bases from a newly made strand
-DNA polymerase 2, 4 and 5: repair damaged DNA
dsDNA: double strand DNA
Fidelity: accuracy of the process
Conservative model: 1 new DNA 1 old DNA (both parental strands stay together)
Semiconservative model: 2, 1 parental strand, 1 daughter strand
Dispersive model: parental and daughter strand are interspersed
ON EXAM: For example: Percentage of mixed bands after 8 generations (DRAW!!!)
15N (heavier) -> lighter 14N added -> bands go from heavy to half heavy -> bands go to half
heavy/light -> Semiconservative model
Bacterial DNA replication:
1 origin of replication in both ways (bidirectional)
oriC: origin of Chromosomal replication
- AT- rich region (easier to break hydrogen bonds)
- DnaA boxes
- GATC methylation sites
-> DnaA proteins bind to DnaA boxes
-> DnaA proteins recruit other proteins
-> DNA bends
-> AT-rich region separates
-> DNA helicase: breaks the hydrogen bonds between the DNA strands.
Dam (DNA adenine methyltransferase): methylates adenine
Newly replicated DNA/daughter strand GATC is not methylated
DNA needs to be methylated before replication can start again
Summary enzymes:
-DNA helicase: breaks the hydrogen bonds between the DNA strands.
-Topoisomerase II: alleviates positive supercoiling. (DNA gyrase)
-Single-strand binding proteins: keep the parental strands apart.
-Primase: synthesizes an RNA primer.
-DNA polymerase I: removes the RNA primers and fills in with DNA
-DNA polymerase III: synthesizes a daughter strand of DNA.
-DNA ligase: covalently links the Okazaki fragments together.
DNA polymerase
-DNA polymerase I: removes the RNA primers and fills in with DNA
-DNA polymerase III: sigma subunit synthesizes a daughter strand of DNA
Sigma subunit + 9 subunits = holoenzyme
Processive enzyme: an enzyme, which glides along the template strand and does not
dissociate from it while catalyzing attachment of nucleotides.
Proofreading function: ability to remove mismatched bases from a newly made strand
-DNA polymerase 2, 4 and 5: repair damaged DNA
