1. 12.2 assessment
Answers

2. Why is DNA replication called semiconservative?
Parental strands of DNA separate, serve as templates, and produce DNA molecules that have one strand of parental DNA and one strand of new DNA.

3. 2. When does DNA replication occur in mitosis and meiosis? Interphase 3. What are the three stages of DNA replication? Unwinding Base pairing Joining

4. 4. What is the name of enzyme that unzips the DNA before replication?
DNA helicase
5. What is a replication fork and where is it located on the strand of DNA?
the replication fork is where DNA has opened up and is being replicated.
It is located between the parental DNA

5. 6. After the enzyme opens up the DNA strand for replication, what are the two strands of DNA called?
Leading strand and lagging strand
7. What is the orientation of the two strands?
Leading strand 5’ to 3’
Lagging strand 3’ to 5’

6. 8. What does the enzyme RNA primase do
8. What does the enzyme RNA primase do? RNA primase adds a short segment of RNA, called an RNA primer, on each parental DNA strand. 9. What does DNA polymerase do? adds complementary nucleotides to the RNA primer on the new DNA strand

7. 10. Nucleotides are added to which end of the new DNA strand?
the 3’ end of the new DNA strand
How is the leading strand copied and why is it copied that way?
It is copied continuously in one piece.
It is copied that way because it is oriented in the right direction for DNA replication.

8. How is the lagging strand copied and why is it copied that way?
It is copied discontinuously and into small segments called Okasaki fragments.
It is copied that way because it is in the opposite direction of replication.

9. What happens to the RNA primer on the new strand of DNA?
DNA polymerase removes the RNA primer
14. What is the function of the enzyme ligase?
Connects the Okasaki fragments on the lagging strand

10. 15. What is the difference between eukaryotic DNA or prokaryotic DNA
15. What is the difference between eukaryotic DNA or prokaryotic DNA? Eukaryotic DNA is located in nucleus. It can unwind in multiple areas. Prokaryotic DNA is located in the cytoplasm and it is circular.

11. 16. If the parent strand of DNA is 5’ ATT GCT ACC 3’ , the complimentary daughter strand is TAA CGA TGG 17. Why is it important for DNA to copy itself? To ensure that the same DNA gets passed along to new cells made in meiosis and that offspring receives the proper amount of DNA from parents

12. 18. What has to reform between the bases of parental DNA and new DNA
18. What has to reform between the bases of parental DNA and new DNA? Hydrogen bonds

13. 19. What would be the result if DNA replication took place after mitosis occurred? Some of the daughter cells might have no DNA, some might not have copies of all chromosomes and some might have double the amount of DNA.

14. 20. How does base pairing during replication ensure that the strands produced are identical to the original strand? Each base only binds to its complement

15. Why is eukaryotic DNA replication more complex than it is in bacteria?
Chromosome in eukaryotes are more complex and bigger. There are many areas of replication on eukaryotic DNA. Prokaryotes only have one origin of replication.

16. 22. Why is it important for eukaryotic DNA to replicate in multiple places? Eukaryotic DNA is complex and might composed of up to 1 million pairs. DNA replication can occur faster when replicated in multiple areas.