Replication of DNA

Key Area 2

Name of the enzyme that replicates strands of DNA

DNA polymerase

Name of a molecule that must be present for DNA replication to take place

Primers

Describe the role of DNA polymerase during DNA replication

Replicates DNA nucleotides in a 5’ to 3’ direction

Give one practical of PCR

Forensic science

During PCR the sample is heated to around 95°C. State what happens to the DNA at this temperature

Hydrogen bonds between bases are broken and strands of DNA are separated

During PCR, the temperature is lowered to approximately 50-60°C after the DNA strand have separated. State what happens at this stage

Primers to anneal to their complementary target sequences

Explain why a heat tolerant DNA polymerase is required during PCR

So it doesn’t denature due to high temperature used in PCR

During PCR, DNA is heated to between 70-80°C. State what happens at the DNA at this temperature

For heat tolerant DNA polymerase to replicate the region of DNA

State the role of primers during PCR

Indicates a starting point for DNA polymerase to being replication

State on commercial use of PCR

Settle paternity suits

Explain why DNA polymerase produces a lagging strand during DNA replication

DNA polymerase replicates in a 5’ to 3’ direction only

State what happens after the heat tolerant DNA polymerase to replicate the region of DNA

The cycle continues to increase the number of copies of DNA

State the role of DNA ligase during DNA replication

Joints the fragments together in the lagging strand

State the role of the DNA polymerase during DNA replication

Adds complimentary nucleotide in a 5’ to 3’ direction