DNA Replication

Question 1

Molecule made up of two strands twisted in double helix

Complementary strands

A-T
C-G

Answer 1

DNA

Question 2

First step in DNA replication is separation of two strands (unzipping) by the enzyme

Answer 2

DNA helicase

Question 3

Separation of the two strands of DNA by helicase result in formation of

The separated strands provide a template for creating a new strand of DNA

Answer 3

replication fork

Question 4

The process is started by this enzyme making a small piece of RNA called a primer

This marks the starting point for the construction of the new strand of DNA.

Answer 4

DNA Primase

Question 5

Next, an enzyme binds to the primer (beginning at the 3’ end) and will make a new strand of DNA

This enzyme can only add DNA bases in one direction from 5’ end to 3’ end

Synthesis of DNA in the 5’ to 3’ direction

The newly synthesized strand is complementary and antiparallel to the parental strand used as template

Answer 5

DNA Polymerase III

Question 6

The lagging strand at the opposite end of the fork cannot be made in a continuous way because it runs in the opposite direction.

The DNA polymerase III can therefore only make this strand in a series of small chunks called

Answer 6

Okazaki fragments

Question 7

Synthesis of lagging strand is started by creating an RNA primer.

This enzyme thens add a short row of DNA bases in a 5’ to 3’ direction beginning at the 3’ to 5’ end

Answer 7

DNA polymerase III

Question 8

The next primer is then added further down the lagging strand.

Another fragment is made and the process continues again

Answer 8

Okazaki fragment

Question 9

After the process is made, this enzyme removes all the RNA primers from both strands of the DNA

Answer 9

DNA Polymerase I Exonuclease

Question 10

The gaps left behind removal of primer are filled up with nucleotide bases by this enzyme

Answer 10

DNA polymerase

Question 11

Seas up fragments of DNA in both strands to form a continuous strand

Answer 11

DNA ligase