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DNA Replication

When replication happens, DNA polymerase, meselson & stahl, roles of accessory proteins, synthesis of DNA on leading strand, synthesis on DNA on lagging strand, diagram of process

When replication happens, DNA polymerase, meselson & stahl, roles of accessory proteins, synthesis of DNA on leading strand, synthesis on DNA on lagging strand, diagram of process

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These flashcards delve into the intricate process of DNA replication, suitable for university-level biology students. They cover key components like DNA polymerase, helicase, and the roles of leading and lagging strands, along with the processes of unwinding the helix, synthesizing RNA primers, and binding proteins. The flashcards also explore the differences between eukaryotes and prokaryotes in replication timing. This set is invaluable for students aiming to grasp the molecular mechanisms behind DNA replication and its biological significance.
Cartes-fiches
11
Utilisateurs
1
Langue
Anglais
Catégorie
Biologie
Niveau
Université
Créé / Mis à jour
05.01.2020 / 13.01.2020
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Cartes-fiches

When does replication take place in eukaryotes and prokaryotes?

DNA replication in eukaryotes in S-Phase and prokaryotes replicate constantly

DNA Polymerase (role, how does it work)

DNA Polymerase is an enzyme that synthesizes DNA molecules from the leading and lagging strand

5' to 3' prime polymerase activity -> leading and lagging strand (lagging strand are sequences called okazaki fragments)

ALWAYS starts at a free 3' OH group!

DNA Helicase 

Unwinds the double helix into two single strands (leading & lagging strands), which act like two templates by breaking hydrogen bonds between bases 

RNA Primer

DNA Polymerase can extend chains but cannot start them (doesn't know where to start). The primer is the starting point ((a short chain of nucleotides that binds to the template)

DNA Primase 

DNA Primase binds to template strand and snythesizes RNA Primer (for DNA Polymerase)

Topoisomerase 

Relaxes helix and reduces torsion, that helicase can unwind the helix easily

Ligase 

Repares and connects DNA fragments 

Single strandend binding protein

Keeps the single DNA strands stable and separate from each other after the helicase undwinded the helix. DNA Polymerase can access the right sequences better 

Sliding Clamp

Is a protein fold which binds to the DNA Polymerase and stabilizes it and also prevents it from dissociating

Protein-protein interaction is stronger than polymerase directly with the template. 

Sliding clamp can increase the rate of DNA synthesis by a 1000-fold 

Meselson & Stahl (experiment,data,conclusion)

They grew DNA in heavy nitrogen, which makes DNA heavy. Through centrifugation of the DNA the heavy DNA was separated from light DNA. The DNA grew in a light isotope of nitrogen for a generation and the DNA had intermediate density. Two more generations were replicated from this one and the results show, that the semiconservative replication is right. Helix is unwinded and both template strands are "copied".

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