DNA Replication Lagging Strand

[firecloak]

Order the following activities required for DNA replication on the lagging strand in eukaryotes. One activity is used more than once and another activity is not used at all.

A. DNA Polymerase
B. RNA polymerase
C. DNAse
D. RNAse
E. DNA ligase

I'm guessing RNA polymerase isn't used, because we're building DNA, not RNA here. I can't seem to find out what DNAse does though.

[canalon]

Hint: synthesis of Okazaki fragments...

[firecloak]

Is this the order:

DNA polymerase
RNAse (remove primer)
DNA polymerase (add nucleotides to where the primer was)
DNA Ligase

DNAse breaks up DNA at the phosphodiester bond, and RNA polymerase makes RNA. I still don't know which one of these isn't used.

[canalon]

On your way. How are the primers made?

[BeyazRus]

Primers made by primase enzyme. However, it is not found in question. After helicase enzyme seperate two strands, Primase adds primers. After then, the order is what firecloak said.

DNA polymerase
RNAse (remove primer)
DNA polymerase (add nucleotides to where the primer was)
DNA Ligase

[canalon]

Yes but what kind of family does the primase belong to? Considering it is making RNA...
And considering that the question is about the type of activity rather than the exact enzyme, the offered answer makes sense.

[BeyazRus]

Oh My! You are right!

Primase is actually RNA polymerase. So the order should be like that;

• RNA polymerase (add primer)
• DNA polymerase (replicate)
• RNAse (remove primer)
• DNA polymerase (add nucleotides to where the primer was)
• DNA Ligase (ligate okazaki fragmants)

Thanks canalon. I learned something from you today.