DNA Replication Lagging Strand

Genetics as it applies to evolution, molecular biology, and medical aspects.

Moderators: honeev, Leonid, amiradm, BioTeam

Post Reply
firecloak
Garter
Garter
Posts: 2
Joined: Fri Sep 17, 2010 2:07 am

DNA Replication Lagging Strand

Post by firecloak » Fri Sep 17, 2010 2:14 am

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.

User avatar
canalon
Inland Taipan
Inland Taipan
Posts: 3909
Joined: Thu Feb 03, 2005 2:46 pm
Location: Canada

Post by canalon » Fri Sep 17, 2010 6:04 pm

Hint: synthesis of Okazaki fragments...
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

firecloak
Garter
Garter
Posts: 2
Joined: Fri Sep 17, 2010 2:07 am

Re: DNA Replication Lagging Strand

Post by firecloak » Fri Sep 17, 2010 7:03 pm

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.

User avatar
canalon
Inland Taipan
Inland Taipan
Posts: 3909
Joined: Thu Feb 03, 2005 2:46 pm
Location: Canada

Post by canalon » Mon Sep 20, 2010 9:26 pm

On your way. How are the primers made?
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

BeyazRus
Garter
Garter
Posts: 12
Joined: Sun Sep 19, 2010 8:07 pm

Re: DNA Replication Lagging Strand

Post by BeyazRus » Tue Sep 21, 2010 2:33 pm

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

User avatar
canalon
Inland Taipan
Inland Taipan
Posts: 3909
Joined: Thu Feb 03, 2005 2:46 pm
Location: Canada

Post by canalon » Tue Sep 21, 2010 7:24 pm

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.
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

BeyazRus
Garter
Garter
Posts: 12
Joined: Sun Sep 19, 2010 8:07 pm

Re: DNA Replication Lagging Strand

Post by BeyazRus » Tue Sep 21, 2010 10:25 pm

Oh My! :D 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. :D

Post Reply

Who is online

Users browsing this forum: No registered users and 0 guests