DNA synthesis for E. coli

Question 1

begin at, terminates at site

Answer 1

oriC and ter.

Question 2

primase

Answer 2

an RNA polymerase that synthesizes short RNA called primers. Primers bind to DNA by complementary base pairing, anitparallel

Question 3

fn of 5’–>3’ polymerase activity

Answer 3

adds nucleotide at the free 3’ OH end of RNA or DNA. fixes error

Question 4

fn of 3’–>5’ exonuclease activity

Answer 4

removes nucleotide at the 3’ OH end. proofreading

Question 5

fn of 5’–>3’ exonuclease activity

Answer 5

removes nucleotide at the 5’ OH end. fn in lagging strand synthesis

Question 6

DNA ligase

Answer 6

links adjacent fragments of DNA by process called ligation. this is anabolism and requires nrg

Question 7

initiation of replication

Answer 7

after the 2 stands of DNA are separated, the primase synthesizes a short piece of RNA complementary and anti parallel to oriC. this provides free 3’ OH group needed by DNA pol III

Question 8

lagging strand synthesis is discont so

Answer 8

primase synthesize primers for DNA pol III. Pol III adds dNTPs until it reaches the 5’ end of the next fragment. then stops and dissociates

Question 9

fn of Pol I in lagging strand

Answer 9

removes the primer and fills in gaps with dNMP. done one nuclotide at a time. Pol I removers NMP (primer) from 5’ end of one fragment using 5’—>3’ exonuclease activity and adds dNMP to the 3’ of other fragment using 5’—>3’ polymerase activity. the substrate is dNTP

Question 10

ligation of DNA fragments

Answer 10

DNA ligase links adjacent fragments of DNA. DNA ligases uses ATP or NAD+ as source of nrg. It transfers an AMP to 5’ phosphate of one fragment. then the `bond is hydolyzed. AMP is displace and nrg is used to form bond btwn two fragments