Quiz
DP Biology
DNA Replication HL
Name: ____________________
Total – 10 Marks
1. What is the role of ligase in DNA replication
(1)
Joins Okazaki fragments together
2. What is the name given to the short sections of DNA formed on the lagging strand?(1)
Okazaki fragments
3. What is the role of helicase
(1)
Separate DNA strands by breaking hydrogen bonds between complementary base pairs
4. What are the two factors that limit the activity of DNA polymerase III
i.
Can only add nucleotides in a 5 to 3 direction (thus synthesis occurs in opposite
directions on the two strands)
ii. Can only add nucleotides ot pre-existign nucleotides (this the need for an RNA primer)
(2)
5. What is the role of DNA polymerase III in replication
Adds nucleotides to the growing DNA strand
(1)
6. What is the role of primase
Adds RNA primer to DNA strand so that DNA polymerase III can start to add DNA
nucleotides
(1)
7. Why is it necessary to have an RNA primer
Because DNA polymerase III can only add nucleotides to pre-existing nucleotides
(1)
8. What is the role of DNA polymerase I
Removes RNA pirmer and replaces it with DNA
(1)
9. What is meant by the term lagging strand.
The strand of DNA which is formed in short sections (Okazaki fragments) and always
lags behind the leading strand.
(1)