Replication of DNA

Question 1

what replicates DNA?

Answer 1

DNA polymerase

Question 2

what is primers needed for?

Answer 2

DNA polymerase needs primers to start replication.

Question 3

what is a primer?

Answer 3

a short strand of nucleotide which binds to the 3’ end of the template DNA strand allowing DNA polymerase to add DNA nucleotides

Question 4

stages of DNA replication:

Answer 4

1. DNA is unwound and hydrogen bonds break between bases to form 2 template strands.
2. primer is added to the 3’ end of each strand.
3. DNA polymerase adds nucleotides to each of the primers
4. another primer is added to lagging strand by DNA polymerase as more DNA is unzipped.
5. DNA ligase joins the fragments of the lagging strand together.

Question 5

what does PCR do?

Answer 5

amplifies DNA using complementary primers for specific target sequences

Question 6

what are primers in PCR?

Answer 6

they are short strands of nucleotides which are complementary to the target sequence at the two ends of the region of DNA to be amplified.

Question 7

stages of PCR?

Answer 7

1. DNA is heated to between 92-98 degrees breaking hydrogen bonds between bases and separating the strands.
2. it is the cooled to between 50-65 degrees allowing primers to bind to target sequence.
3. it is then heated to between 70-80 degrees for heat-tolerant DNA polymerase

Question 8

what can PCR be used for?

Answer 8

solve crimes, settle paternity suits and diagnose genetic disorders.