Unit: 1 - Replication of DNA

Question 1

What does DNA polymerase do in DNA replication?

Answer 1

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

Question 2

What does DNA ligase do in DNA replication?

Answer 2

DNA ligase joins fragments of DNA together.

Question 3

How many times is PCR usually repeated?

Answer 3

At least 30 times

Question 4

What is a practical application of PCR?

Answer 4

PCR is involved in the process of DNA sequencing and has allowed amplification of DNA from ancient sources, such as Neanderthal bones, enabling in-depth DNA analysis. PCR also has forensic applications, allowing minute quantities of DNA from a crime scene to be amplified, sequenced, and compared to DNA sequences from suspects. PCR has medical applications, for example the diagnosis of human immunodeficiency virus (HIV). Finally, PCR can be used to settle paternity disputes by amplifying and comparing a child’s DNA to their potential father.