EXAM 2- CH 6, 7, 9 Flashcards
What question was answered in the Meselson and Stahl experiment
that DNA was semi-conservative
materials used in Meselson and Stahl experiment
- bacteria
- 15N (heavy)
- 14N (light)
procedure of Meselson and Stahl experiment
- grew bacteria in 15N medium and then put bacteria in 14N medium
- centrifuged bacteria
results of Meselson and Stahl experiment
- found that more 14N was found in the DNA of the bacteria with each generation
- DNA replication is semi-conservative
true or false: DNA Replication is fundamentally similar in eucaryotes and bacteria
true
what are the 3 phases of replication
- initation
- elongation
- termination
what occurs in the initation phase of replication
- DNA synthesis begins at ori’s
- formation of replication bubble
what occurs in the elongation phase of replication
polymerization of leading and lagging strand
what occurs in the termination phase of replication
eukaryotes: ends of chromosomes are replicated
function of initiator proteins
- bind to ori to initiate DNA replication
- brings DNA helicase to the region
function of DNA polymerase
- polymerize DNA 5’ —> 3’ direction
- removes RNA primer (exonuclease activity)
- proofread
function of DNA ligase
- forms covalent bonds between nucleotides in the lagging strand
- glue
function of DNA primase
- synthesizes RNA primers
function of DNA helicase
- breaks h bonds between the parent strands
- sizers
function of SSBP
- keeps the single lagging strand separated
- avoids internal hybridization
function of sliding clamp
- protein that keeps DNA polymerase from falling off
- seatbelt
function of clamp loader
- loads the sliding clamp onto DNA
function of topoisomerase/gyrase
- unwinds DNA supercoiling
- cuts phosphodiester bond in backbone
- conditioner
how many forks are there in a replication bubble
2
what nucleotides are by the ori
lots of A and T
why is the ori rich in A and T
less h bonds to break
how many primers are required on the leading strand
1
how many primers are required on the lagging strand
a lot
what is the template in DNA replication
parent strand