MIC 102 MT 2 Questions With Complete Solutions
Structure of DNA
5'-->3'
Anti-parallel
1 ring=pyrimidine
2 ring=purine
A(2) + T(1) 2 H-bonds
G(2)+C(1) 3 H-bonds
G and C have 3
DNA Replication
Semi-conservative
DNA Pol replicates 1000nt/second
*errors only 1/10billion bp Why does the origin (oriC) have runs of A:T base pairs?
Easy to break apart, only 2 H-bonds
Alot of G:C base pairs at end repication to stop 3H bonds harder
to melt
What holds Strands apart after melted?
SSB single strand binding proteins
What melts the DNA strand open?
Helicase
What relaxes the DNA strand to later be opened?
Topoisomerase (DNA Gyrase)
RNA Primer
required for okazaki fragments to polymerize in 5'-->3' direction
Steps in DNA replication
1. Initiation
2. Elongation
3. Termination
Initiation SeqA dissociates from fully methylated binding sites on oriC
-At high [DnaA-ATP], it binds DnaA boxes at oriC and melts the H-bonds at the origin
-SSB protein keeps strands apart
-Helicase breaks H-bonds, seperates strands
-replisome assembles onto replication bubble
-Primase(DNA-dependent RNA polymerase) makes a short primer
Elongation
A topoisomerase (DNA gyrase) relaxes supercoiling ahead of replication fork
Leading& laggind strand synthesis:
Slidding clamp allow DNA Pol to move along template and be processive
-DNA Pol proofreads as it extends the DNA with a 3'--> 5" exonuclease activity Leading strand synthesis
- DNA polymerase extends from primer,adds nucleotides 5'-3'
Replisome
is a complex molecular machine that carries out replication of DNA.
Termination
Terminator (ter) sequences are bound by protein that inhibits helicase and prevents the replisome from moving past terminator
- daughter chromosome concatenates(linked together) gets resolved by a topoisomerase
Newly replicated DNA is being methylated by DAM methylase
Structure of DNA
5'-->3'
Anti-parallel
1 ring=pyrimidine
2 ring=purine
A(2) + T(1) 2 H-bonds
G(2)+C(1) 3 H-bonds
G and C have 3
DNA Replication
Semi-conservative
DNA Pol replicates 1000nt/second
*errors only 1/10billion bp Why does the origin (oriC) have runs of A:T base pairs?
Easy to break apart, only 2 H-bonds
Alot of G:C base pairs at end repication to stop 3H bonds harder
to melt
What holds Strands apart after melted?
SSB single strand binding proteins
What melts the DNA strand open?
Helicase
What relaxes the DNA strand to later be opened?
Topoisomerase (DNA Gyrase)
RNA Primer
required for okazaki fragments to polymerize in 5'-->3' direction
Steps in DNA replication
1. Initiation
2. Elongation
3. Termination
Initiation SeqA dissociates from fully methylated binding sites on oriC
-At high [DnaA-ATP], it binds DnaA boxes at oriC and melts the H-bonds at the origin
-SSB protein keeps strands apart
-Helicase breaks H-bonds, seperates strands
-replisome assembles onto replication bubble
-Primase(DNA-dependent RNA polymerase) makes a short primer
Elongation
A topoisomerase (DNA gyrase) relaxes supercoiling ahead of replication fork
Leading& laggind strand synthesis:
Slidding clamp allow DNA Pol to move along template and be processive
-DNA Pol proofreads as it extends the DNA with a 3'--> 5" exonuclease activity Leading strand synthesis
- DNA polymerase extends from primer,adds nucleotides 5'-3'
Replisome
is a complex molecular machine that carries out replication of DNA.
Termination
Terminator (ter) sequences are bound by protein that inhibits helicase and prevents the replisome from moving past terminator
- daughter chromosome concatenates(linked together) gets resolved by a topoisomerase
Newly replicated DNA is being methylated by DAM methylase
