BMB 401 Lecture Notes - Lecture 3: Photon, Non-Homologous End Joining, Pyrimidine Dimer

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aquamarinemink463

16 Dec 2016

School

University of Miami

Department

Biochemistry and Molecular Biology

Course

BMB 401

Professor

Farooq

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Document Summary

The dna polymerase needs a template for obvious reasons. It has to copy something so after the dna is unwound a single strand (ssdna) can then function as the template to be copied. It the(cid:374) (cid:272)atal(cid:455)zes the s(cid:455)(cid:374)thesis of a daughter stra(cid:374)d i(cid:374) a 5" (cid:1007)" dire(cid:272)tio(cid:374) (cid:271)e(cid:272)ause dna pol(cid:455)(cid:373)erase adds free (cid:374)u(cid:272)leotides to the (cid:1007)"-oh group. To get this ssdna the dna is unwound at the replication origin to form the replication bubble. The issue is dna polymerase cannot start synthesis of a new strand, it can only extend an exposed strand. To overcome this dna primase synthesizes short rna primers and these join to the exposed parent dna strands as they separate at the replication origin. This is then able to be extended by dna polymerase. The leading strand requires one primer whilst the lagging strand requires as many primers as there are okazaki fragments.

Related Questions

DNA replication is Escherichia coli begins at a unique site called the:

	origin of responsiveness.
	origin of replication.
	replication origination site.
	oriDNA.
	start site.

During the replication of prokaryotic DNA,

	both strands are simultaneously synthesized in a continuous manner.
	one strand is synthesized in a continuous manner and the other is synthesized by reverse transcription.
	both stands are simultaneously synthesized in short pieces which are later joined by DNA ligase.
	one strand is synthesized continuously and the other is synthesized in short segments.
	both strands are synthesized continuously, but the lagging strand is synthesized only after the leading strand has been completely replicated.

The primase enzyme

	synthesizes a short stretch of RNA complementary to a part of the template DNA strand.
	synthesizes a short stretch of DNA that is complementary to a part of the template strand of DNA.
	acts as the recognition site to which DNA polymerases bind to start the replication process.
	replaces the RNA primers used to initiate DNA replication with DNA polymerase.
	ligates the nicks formed by discontinuous replication along the lagging strand.

taupetrout830

As the two parental (template) DNA strands separate at a replication fork, each of the strands is separately copied by a DNA polymerase III (orange), producing two new daughter strands (light blue), each complementary to its respective parental strand. Because the two parental strands are antiparallel, the two new strands (the leading and lagging strands) cannot be synthesized in the same way.Drag each phrase to the appropriate bin depending on whether it describes the synthesis of the leading strand, the synthesis of the lagging strand, or the synthesis of both strands.a. multiple primers needed b. daughter strand elongates toward replication fork c. only one primer neededd. synthesized 5' to 3'e. daughter strand elongates away from replication fork f. made continuously g. made in segments

Why does each replication fork require both leading and lagging strand synthesis?
Select the 2 reasons below.

A) Because DNA synthesis is semi-conservative.
B) Because DNA polymerases must synthesize DNA 3' to 5'.
C) Because the DNA templates are antiparellel.
D) Because DNA polymerase only synthesizes DNA in one direction.

I chose A and C but got it wrong.
Can anyone explain this?

BMB 401 Lecture Notes - Lecture 3: Photon, Non-Homologous End Joining, Pyrimidine Dimer

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