KA1.2: DNA replication

when does DNA replicated ?

• Prior to cell division, DNA is replicated by a DNA polymerase

What does DNA polyemrase need to start replication?

Dna polymerase needs primers to start replication

What is a primer?

A primer is a short strand of nucleotides which binds to the 3’ end of the template DNA strand allowing polymerase to add DNA nucloetides.

What are the requirements for DNA replication?

• DNA template

• Enzymes - DNA polymerase and ligase

• ATP

• free DNA nucleotides

• Primer

State 4 step process of DNA replication?

1. DNA is unwound and hydrogen bonds between the bases break forming two template strands

2. Dna polymerase needs primers to start replication

3. DNA polymerase adds DNA nucleotides, using complementary base pairing, to the deoxyribose 3’ end of the new DNA strand which is forming

4. This results in the leading strand being replicated continuously

5. The lagging strand being replicated in fragments which are then joined together by the enzyme ligase