4.2

Question 1

Semi conservative

Answer 1

Semi conservative strand contains one original DNA strand and one new strand. this allows DNA to duplicate

Question 2

Dna replication experiment

Answer 2

By Meselson and Stahl with centrifugation showing replication is semi conservative

Question 3

DNA polymerase

Answer 3

In bacteria polymerase 3 responsible for replication

In eukaryotes DNA polymerase alpha, delta and e are responsible for nuclear DNA.

DNA polymerase y is responsible for replication in mitochondrial DNA.

Synthesis 5-3 prime

Question 4

DNA polymerases -prokaryotes

Answer 4

DNA polymerase 1 - replication and repair, exonuclease activity both directions

DNA polymerase 2 - DNA repair, exonuclease activity in 3’-5’ sense

DNA polymerase 3 - DNA replication and revision, exonuclease activity in 3’-5’ sense

Question 5

DNA polymerase eukaryotes

Answer 5

Polymerase gamma - located in mitochondria, replication of genetic material in it.

Alpha, delta and e most active in cell division process, main function production of DNA copies.

DNA polymerase beta - most activity when cells not dividing - DNA Repair

Gamma, delta and e have 3’-5’ exonuclease activity

Question 6

Origin of replication

Answer 6

Where replication begins.

A large number of enzymes and proteins involved in molecular mechanism of replication called replisomes

Question 7

Origin of replication in prokaryotes

Answer 7

E. coli has 245 bp

Question 8

ARS

Answer 8

Part of origin of replication in yeast.

4 regions ACS,B1,B2,B3

Has 11 bp.

any mutation nullifies the original function - if mutations in b1,2,3 will decrease but not prevent function

ORC binds to ASC and B1