Amoeba Sisters “DNA Replication: The Cell’s Extreme Team Sport”
Video Worksheet
Go to https://www.youtube.com/watch?v=5qSrmeiWsuc
(Less than 8 minutes).
While watching, complete this worksheet
1.
DNA Replication means Making more DNA
2.
Where does DNA replication occur? In the nucleus
3.
This video clip is actually going to focus on the types of cells that DO have a nucleus
4.
...they’re known as eukaryote
5.
When….this typically happens in during a stage known as interphase.
6.
In fact, cells the cells replicate its DNA before division processes like Mitosis and
Meiosis.
7.
Key players in DNA replication:
a. When something ends in “ASE” it is very possible that it’s an enzyme.
b. Helicase- the unzipping enzyme.
c. DNA Polymerase - the builder.
d. Primase - the initializer. Primase makes the primer so that DNA
polymerase can figure out where to start to work. So know what’s
interesting about the primer that it makes? It’s actually a piece of RNA.
e. Ligase - the gluer. It helps glue DNA fragments together.
8.
DNA replication starts at a certain part called the origin.
9.
At the origin, I. Helicase unwinds DNA
10. II. SSB proteins bind to DNA strands
11. III. Primase creates primer.
12. IV. DNA Polymerase begins to build
13. You have two strands right? (of DNA). They are not identical; they complement
each other. They also are antiparallel so they don’t really go in the same direction.
14. DNA either goes 5’ to 3’(prime) or 3’ to 5’(prime)
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Amoeba Sisters “DNA Replication: The Cell’s Extreme Team Sport”
Video Worksheet
15. The sugar of DNA is part of the backbone of DNA. It has carbons.
16. Carbons are numbered right after the oxygen in a clockwise direction.
17. The 5’/3’ are outside the ring.
18. DNA Polymerase can only work in the 5’ to 3’(prime) direction.
19. The strand that runs 5’ to 3’(prime) is fine. It is called the leading strand.
20. But the other strand will make it a little tricky.
21. On the lagging strand, DNA Polymerase can only go in the 5’ to 3’ (prime) direction.
22. RNA Primase has to set a lot of extra primers down to do that. It takes longer too.
23. This strand is called the lagging strand.
24. On the lagging strand you get little fragments of synthesized DNA called Okazaki
fragments.
25. Ligase, that’s the gluing enzyme, has to take care of the gaps in the Okazaki
fragments.
26. At the end you have two identical double helix DNA molecules.
27. We call this semi-conservative because the strands each contain one old, original
strand and one newly made.
28. DNA Polymerase is just awesome, it has proofreading ability. It rarely makes a
mistake.
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