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
Set of flashcards Details
| Flashcards | 11 |
|---|---|
| Language | English |
| Category | Biology |
| Level | University |
| Created / Updated | 05.01.2020 / 13.01.2020 |
| Weblink |
https://card2brain.ch/box/20200105_dna_replication
|
| Embed |
<iframe src="https://card2brain.ch/box/20200105_dna_replication/embed" width="780" height="150" scrolling="no" frameborder="0"></iframe>
|
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".
DRAW THE WHOLE PROCESS
ON PAPER!
